amniotic fluid dynamics of amniotic fluid
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Jul 30, 2024
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About This Presentation
dynamics of amniotic fluid
Slide Content
Presenter-Dr Swathi. P.
MS (OBG)
Moderator-Dr OmkarMurthy
SSMC Tumkur
AMNIOTIC FLUID
MS (OBG)
Moderator-Dr OmkarMurthy
SSMC Tumkur
AMNIOTIC FLUID
CONTENTS:
•Definition
•Introduction
•Physiology of amniotic fluid
•SonographicAssessment
•Abnormalities of amniotic fluid
•Uses –Diagnostic / Therapeutic
•Definition
•Introduction
•Physiology of amniotic fluid
•SonographicAssessment
•Abnormalities of amniotic fluid
•Uses –Diagnostic / Therapeutic
Definition:
•Amniotic fluid is a clear, yellowish liquid that surrounds and protects
the unborn baby (fetus) during pregnancy. It is contained in the
amniotic sac.
•Amniotic fluid is a clear, yellowish liquid that surrounds and protects
the unborn baby (fetus) during pregnancy. It is contained in the
amniotic sac.
Introduction:
•Amniotic fluid serves several roles during pregnancy.
•It creates a physical space for fetal movement, which is necessary for
normal musculoskeletal development.
•It permits fetal swallowing—essential for gastrointestinal tract
development, and fetal breathing—necessary for lung development.
•Amniotic fluid guards against umbilical cord compression and
protects the fetus from trauma.
•Amniotic fluid serves several roles during pregnancy.
•It creates a physical space for fetal movement, which is necessary for
normal musculoskeletal development.
•It permits fetal swallowing—essential for gastrointestinal tract
development, and fetal breathing—necessary for lung development.
•Amniotic fluid guards against umbilical cord compression and
protects the fetus from trauma.
•It even has bacteriostatic properties.
•Amnionic fluid volume abnormalities may reflect a problem with fluid
production or its circulation, such as underlying fetal or placental
pathology.
•These volume extremes may be associated with increased risks for
adverse pregnancy outcome.
•Amnionic fluid volume abnormalities may reflect a problem with fluid
production or its circulation, such as underlying fetal or placental
pathology.
•These volume extremes may be associated with increased risks for
adverse pregnancy outcome.
DEVELOPMENT
•Along with the changes in the trophoblast, on the 8th day, the
embryoblastdifferentiates into bilaminargerm disc which consists of
dorsal ectodermallayer of tall columnar cells and ventral endodermal
layer of flattened polyhedral cells.
•The bilaminargerm disc is connected with the trophoblastby
mesenchymalcondensation, called connecting stalk or body stalk
which later on forms the umbilical cord .
•Along with the changes in the trophoblast, on the 8th day, the
embryoblastdifferentiates into bilaminargerm disc which consists of
dorsal ectodermallayer of tall columnar cells and ventral endodermal
layer of flattened polyhedral cells.
•The bilaminargerm disc is connected with the trophoblastby
mesenchymalcondensation, called connecting stalk or body stalk
which later on forms the umbilical cord .
•Two cavities appear one on each side of the germ disc.
•(1) On 12th postovulatory day, a fluid filled space appears between
the ectodermallayer and the cytotrophoblastwhich is called amniotic
cavity.
•Its floor is formed by the ectoderm and the rest of its wall by
primitive mesenchyme.
•(2) The yolk sac appear on the ventral aspect of the bilaminardisk
and is lined externally by the primitive mesenchymeand internally by
the migrating endodermalcells from the endodermallayer of the
germ disc
•(1) On 12th postovulatory day, a fluid filled space appears between
the ectodermallayer and the cytotrophoblastwhich is called amniotic
cavity.
•Its floor is formed by the ectoderm and the rest of its wall by
primitive mesenchyme.
•(2) The yolk sac appear on the ventral aspect of the bilaminardisk
and is lined externally by the primitive mesenchymeand internally by
the migrating endodermalcells from the endodermallayer of the
germ disc
•Amniogenic cells line the inner surface of
trophoblast
•Derived from fetal ectoderm of the embryonic disc
•Fluid accumulates slowly at first, but ultimately
the fluid-filled cavity becomes large enough to
obliterate the chorionic cavity;
the amnion and the chorion come in
loose contact by their mesenchymal layers.
trophoblast
•Derived from fetal ectoderm of the embryonic disc
•Fluid accumulates slowly at first, but ultimately
the fluid-filled cavity becomes large enough to
obliterate the chorionic cavity;
the amnion and the chorion come in
loose contact by their mesenchymal layers.
•Initially, the cavity is located on the dorsal surface of the embryonic
disk. With the formation of the head, tail and lateral folds, it comes to
surround the fetus.
•Its two growing margins finally merge into the body stalk.
•Thus, the liquor amnii surrounds the fetus everywhere except at its
attachment with the body stalk.
•The amnion is firmly attached to the umbilical cord up to its point of
insertion to the placenta, but everywhere it can be separated from
the underlying chorion.
disk. With the formation of the head, tail and lateral folds, it comes to
surround the fetus.
•Its two growing margins finally merge into the body stalk.
•Thus, the liquor amnii surrounds the fetus everywhere except at its
attachment with the body stalk.
•The amnion is firmly attached to the umbilical cord up to its point of
insertion to the placenta, but everywhere it can be separated from
the underlying chorion.
Physiology of amniotic fluid:
•The maintenance of amniotic fluid is a dynamic process throughout
pregnancy, with differing origins for the amniotic fluid at advancing
gestational age.
•Early in pregnancy, the amnioniccavity is filled with fluid that is
similar in composition to extracellular fluid.
•During the first half of pregnancy, transfer of water and other small
molecules takes place across the amnion—transmembranousflow,
across the fetalvessels on placental surface—intramembranousflow,
and across fetalskin.
•Fetalurine production begins between 8 and 11 weeks, but it does
not become a major component of amnionicfluid until the second
trimester.
•The maintenance of amniotic fluid is a dynamic process throughout
pregnancy, with differing origins for the amniotic fluid at advancing
gestational age.
•Early in pregnancy, the amnioniccavity is filled with fluid that is
similar in composition to extracellular fluid.
•During the first half of pregnancy, transfer of water and other small
molecules takes place across the amnion—transmembranousflow,
across the fetalvessels on placental surface—intramembranousflow,
and across fetalskin.
•Fetalurine production begins between 8 and 11 weeks, but it does
not become a major component of amnionicfluid until the second
trimester.
•This latter observation explains why fetuses with lethal renal
abnormalities may not manifest severe oligohydramnios until after 18
weeks.
•Water transport across the fetal skin continues until keratinization
occurs at 22 to 25 weeks.
•This explains why extremely preterm infants
can experience significant fluid loss
across their skin.
abnormalities may not manifest severe oligohydramnios until after 18
weeks.
•Water transport across the fetal skin continues until keratinization
occurs at 22 to 25 weeks.
•This explains why extremely preterm infants
can experience significant fluid loss
across their skin.
•With advancing gestation, four pathways play a major role in amnionic
fluid volume regulation
•First, fetal urination is the primary amnionic fluid source by the second half
of pregnancy.
•By term, fetal urine production may exceed 1 liter per day—such that the
entire amnionic fluid volume is recirculated on a daily basis.
•Fetal urine osmolality is significantly hypotonic to that of maternal and
fetal plasma and similar to that of amnionic fluid.
•Specifically, the osmolality of maternal and fetal plasma is approximately
280 mOsm/mL, whereas that of amnionic fluid is about 260 mOsm/L.
fluid volume regulation
•First, fetal urination is the primary amnionic fluid source by the second half
of pregnancy.
•By term, fetal urine production may exceed 1 liter per day—such that the
entire amnionic fluid volume is recirculated on a daily basis.
•Fetal urine osmolality is significantly hypotonic to that of maternal and
fetal plasma and similar to that of amnionic fluid.
•Specifically, the osmolality of maternal and fetal plasma is approximately
280 mOsm/mL, whereas that of amnionic fluid is about 260 mOsm/L.
•This hypotonicity of fetal urine—and thus of amnionic fluid—
accounts for significant intramembranous fluid transfer across and
into fetal vessels on the placental surface, and thus into the fetus.
•This transfer reaches 400 mL per day and is a second regulator of
fluid volume (Mann, 1996).
•In the setting of maternal dehydration, the resultant increase in
maternal osmolality favors fluid transfer from the fetus to the
mother, and then from the amnionic fluid compartment into the
fetus.
accounts for significant intramembranous fluid transfer across and
into fetal vessels on the placental surface, and thus into the fetus.
•This transfer reaches 400 mL per day and is a second regulator of
fluid volume (Mann, 1996).
•In the setting of maternal dehydration, the resultant increase in
maternal osmolality favors fluid transfer from the fetus to the
mother, and then from the amnionic fluid compartment into the
fetus.
•An important third source of amnionicfluid regulation is the respiratory
tract.
•Approximately 350 mLof lung fluid is produced daily late in gestation, and
half of this is immediately swallowed.
•Last, fetalswallowing is the primary mechanism for amnionicfluid
resorptionand averages 500 to 1000 mLper day (Mann, 1996).
•Impaired swallowing, secondary to either a central nervous system
abnormality or gastrointestinal tract obstruction, can result in an
impressive degree of hydramnios.
•The other pathways—transmembranousflow and flow across the fetal
skin—account for a far smaller proportion of fluid transport in the second
half of pregnancy.
tract.
•Approximately 350 mLof lung fluid is produced daily late in gestation, and
half of this is immediately swallowed.
•Last, fetalswallowing is the primary mechanism for amnionicfluid
resorptionand averages 500 to 1000 mLper day (Mann, 1996).
•Impaired swallowing, secondary to either a central nervous system
abnormality or gastrointestinal tract obstruction, can result in an
impressive degree of hydramnios.
•The other pathways—transmembranousflow and flow across the fetal
skin—account for a far smaller proportion of fluid transport in the second
half of pregnancy.
Amnionic Fluid Volume Regulation in Late Pregnancy
•Pathway Effect onVolume Approximate Daily
Volume (mL)
•Fetal urination Production 1000
•Fetal swallowing Resorption 750
•Fetal lung fluid secretion Production 350
•Intramembranous flow across
fetal vessels on the placental surface Resorption 400
•Transmembranous flow across
amnionic membrane Resorption Minimal
•Adapted from Magann, 2011; Modena, 2004; Moore, 2010.
•Pathway Effect onVolume Approximate Daily
Volume (mL)
•Fetal urination Production 1000
•Fetal swallowing Resorption 750
•Fetal lung fluid secretion Production 350
•Intramembranous flow across
fetal vessels on the placental surface Resorption 400
•Transmembranous flow across
amnionic membrane Resorption Minimal
•Adapted from Magann, 2011; Modena, 2004; Moore, 2010.
Intermembranous& transmembranous
pathways
▪Asafurtherpathway,rapidmovementsofbothwaterandsolute
occurbetweenamnioticfluidandfetalbloodwithintheplacenta
andmembranes;thisisreferredtoastheintramembranous
pathway.
▪Movementofwaterandsolutebetweenamnioticfluidand
maternalbloodwithinthewalloftheuterusisanexchangethrough
thetransmembranouspathway
pathways
▪Asafurtherpathway,rapidmovementsofbothwaterandsolute
occurbetweenamnioticfluidandfetalbloodwithintheplacenta
andmembranes;thisisreferredtoastheintramembranous
pathway.
▪Movementofwaterandsolutebetweenamnioticfluidand
maternalbloodwithinthewalloftheuterusisanexchangethrough
thetransmembranouspathway
Regulatory mechanisms act at three levels:
•Placentalcontrolofwaterandsolutetransfer.
•Regulationofinflowsandoutflowsfromthefetus:fetalurineflow
andcompositionaremodulatedbyvasopressin,aldosterone,and
angiotensinIIinmuchthesamewayastheyinadults.
•Maternaleffectonfetalfluidbalance:duringpregnancy,thereisa
strongrelationshipbetweenmaternalplasmavolumeandAFV,
•Placentalcontrolofwaterandsolutetransfer.
•Regulationofinflowsandoutflowsfromthefetus:fetalurineflow
andcompositionaremodulatedbyvasopressin,aldosterone,and
angiotensinIIinmuchthesamewayastheyinadults.
•Maternaleffectonfetalfluidbalance:duringpregnancy,thereisa
strongrelationshipbetweenmaternalplasmavolumeandAFV,
Normal amnionicfluid volume:
•Amnionicfluid volume increases from approximately 30 mLat 10
weeks to 200 mLby 16 weeks and reaches 800 mLby the mid-third
trimester (Brace, 1989; Magann, 1997).
•A full-term fetuscontains roughly 2800 mLof water, and the placenta
another 400 mL, such that the term uterus holds nearly 4 litersof
water(Modena, 2004). (Williams)
•Amnionicfluid volume increases from approximately 30 mLat 10
weeks to 200 mLby 16 weeks and reaches 800 mLby the mid-third
trimester (Brace, 1989; Magann, 1997).
•A full-term fetuscontains roughly 2800 mLof water, and the placenta
another 400 mL, such that the term uterus holds nearly 4 litersof
water(Modena, 2004). (Williams)
•It measures about:
•50 mL at 12 weeks,
•400mL at 20 weeks
•1 liter at 36–38 weeks Thereafter the amount diminishes, till
•600–800 mL at term
•As the pregnancy continues post term, further reduction occurs to
the extent of about 200 mL at 43 weeks.
•50 mL at 12 weeks,
•400mL at 20 weeks
•1 liter at 36–38 weeks Thereafter the amount diminishes, till
•600–800 mL at term
•As the pregnancy continues post term, further reduction occurs to
the extent of about 200 mL at 43 weeks.
Characteristics of amniotic fluid:
•Water content and osmolality: at first trimester, amniotic fluid has
an electrolyte composition and osmolality similar to that of fetal and
maternal blood.
•As fetal urine begins to enter the amniotic cavity, amniotic fluid
osmolality decreases compared with fetal blood.
•At term it contains 99% water.
•The osmolality, sodium, urea and creatinine is not significantly
different from the maternal serum.
•Water content and osmolality: at first trimester, amniotic fluid has
an electrolyte composition and osmolality similar to that of fetal and
maternal blood.
•As fetal urine begins to enter the amniotic cavity, amniotic fluid
osmolality decreases compared with fetal blood.
•At term it contains 99% water.
•The osmolality, sodium, urea and creatinine is not significantly
different from the maternal serum.
•The osmolalityis lowest at term (250-260mOsml/kg) compared with
fetalblood osmolalityof 280mOsml/kg water.
•This is a result of extremely hypotonic fetalurine(60-140mOsml/kg
water) in combination of lesser volume of lung fluid.
•An osmolarityof 250 mOsmol/L is suggestive of fetalmaturity.
•The fluid is faintly alkaline with low specific gravity of 1.010. It
becomes highly hypotonic to maternal serum at term pregnancy
fetalblood osmolalityof 280mOsml/kg water.
•This is a result of extremely hypotonic fetalurine(60-140mOsml/kg
water) in combination of lesser volume of lung fluid.
•An osmolarityof 250 mOsmol/L is suggestive of fetalmaturity.
•The fluid is faintly alkaline with low specific gravity of 1.010. It
becomes highly hypotonic to maternal serum at term pregnancy
•Colour: In early pregnancy, it is colorless but near term it becomes
pale straw colored due to the presence of exfoliated lanugo and
epidermal cells from the fetal skin.
•It may look turbid due to the presence of vernix caseosa.
•Abnormal color: has got clinical significance
•Meconium stained (green) is suggestive of fetal distress in
presentations other than the breech or transverse.
•Depending upon the degree and duration of the distress, it may be
thin or thick or pea souped (thick with flakes).
•Thick with presence of flakes suggests chronic fetal distress.
pale straw colored due to the presence of exfoliated lanugo and
epidermal cells from the fetal skin.
•It may look turbid due to the presence of vernix caseosa.
•Abnormal color: has got clinical significance
•Meconium stained (green) is suggestive of fetal distress in
presentations other than the breech or transverse.
•Depending upon the degree and duration of the distress, it may be
thin or thick or pea souped (thick with flakes).
•Thick with presence of flakes suggests chronic fetal distress.
•Golden color in Rh incompatibility is due to excessive hemolysis of
the fetal RBC and production of excess bilirubin.
•Greenish yellow (saffron) in post maturity.
•Dark colored in concealed accidental hemorrhage is due to
contamination of blood.
•Dark brown (tobacco juice) amniotic fluid is found in IUD. The dark
color is due to frequent presence of old HbA
the fetal RBC and production of excess bilirubin.
•Greenish yellow (saffron) in post maturity.
•Dark colored in concealed accidental hemorrhage is due to
contamination of blood.
•Dark brown (tobacco juice) amniotic fluid is found in IUD. The dark
color is due to frequent presence of old HbA
•Constituents of the fluid: In early pregnancy , amniotic fluid is an
ultra filtrate of maternal plasma.
•By the beginning of second trimester , it consist largely of
extracellular fluid which diffuse through the fetal skin, and therefore
reflects the composition of fetal plasma it contains:
•a-Organic, inorganic and cellular constituent.
•b-It contains traces of steroid and non-steroid hormones.
•c-It’s mildly bacteriostatic.
ultra filtrate of maternal plasma.
•By the beginning of second trimester , it consist largely of
extracellular fluid which diffuse through the fetal skin, and therefore
reflects the composition of fetal plasma it contains:
•a-Organic, inorganic and cellular constituent.
•b-It contains traces of steroid and non-steroid hormones.
•c-It’s mildly bacteriostatic.
Composition:
Organic constituents -
•Proteins-0.3 mg/dl
•Glucose-20mg/dl
•Urea-30 mg/dl
•Non protein nitrogen-30mg/dl
•Uric acid –4 mg/dl
•Creatinine -2 mg/dl
•Lipids-50 mg/ dl
•Hormones-insulin,prolactin, renin
Inorganic constituents -Na, K,Cl
Suspended particles -Lanugo,Desqamated fetal skin cells,vernix
caseosa,shedded amniotic cells, cells from the respiratory tract, GIT
Genitourinary tract
Organic constituents -
•Proteins-0.3 mg/dl
•Glucose-20mg/dl
•Urea-30 mg/dl
•Non protein nitrogen-30mg/dl
•Uric acid –4 mg/dl
•Creatinine -2 mg/dl
•Lipids-50 mg/ dl
•Hormones-insulin,prolactin, renin
Inorganic constituents -Na, K,Cl
Suspended particles -Lanugo,Desqamated fetal skin cells,vernix
caseosa,shedded amniotic cells, cells from the respiratory tract, GIT
Genitourinary tract
Function of amniotic fluid:
During pregnancy:
•Act as a shock absorber to protect the fetus from external injury
•Maintains the fetal temprature
•Allows free movement and growth of fetus
•Prevents adhesion formation between the fetal parts and the amniotic sac
•Has some nutritive value because of small amount of protein and salt
content
During pregnancy:
•Act as a shock absorber to protect the fetus from external injury
•Maintains the fetal temprature
•Allows free movement and growth of fetus
•Prevents adhesion formation between the fetal parts and the amniotic sac
•Has some nutritive value because of small amount of protein and salt
content
During Labour:
•It forms hydrostatic wedge to help dilatation of cervix
•During uterine contractions , the amniotic fluid in the intact
membranes prevents interference with placental circulation
•Provides pool for the fetus to excrete urine
•Protect the fetus from the ascending infections by its bactercidal
action
•It forms hydrostatic wedge to help dilatation of cervix
•During uterine contractions , the amniotic fluid in the intact
membranes prevents interference with placental circulation
•Provides pool for the fetus to excrete urine
•Protect the fetus from the ascending infections by its bactercidal
action
Measurement:
•From a practical standpoint, the actual volume of amnionic fluid is rarely
measured outside of the research setting.
•That said, direct measurement and dye-dilution methods of fluid
quantification have contributed to an understanding of normal physiology.
•These measurements have further been used to validate sonographic fluid
assessment techniques.
•The dye-dilution method involves injection of a small quantity of a dye such
as aminohippurate into the amnionic cavity under sonographic guidance.
•The amnionic fluid is then sampled to determine the dye concentration and
hence to calculate the fluid volume in which it was diluted.
•From a practical standpoint, the actual volume of amnionic fluid is rarely
measured outside of the research setting.
•That said, direct measurement and dye-dilution methods of fluid
quantification have contributed to an understanding of normal physiology.
•These measurements have further been used to validate sonographic fluid
assessment techniques.
•The dye-dilution method involves injection of a small quantity of a dye such
as aminohippurate into the amnionic cavity under sonographic guidance.
•The amnionic fluid is then sampled to determine the dye concentration and
hence to calculate the fluid volume in which it was diluted.
•Magannand colleagues (1997) used dye-dilution measurements and
found that the amnionicfluid volume continues to increase with
advancing gestation.
•Specifically, the average fluid volume was approximately 400 mL
between 22 and 30 weeks, doubling thereafter to a mean of 800 mL.
•The volume remained at this level until 40 weeks and then declined
by approximately 8 percent per week thereafter
found that the amnionicfluid volume continues to increase with
advancing gestation.
•Specifically, the average fluid volume was approximately 400 mL
between 22 and 30 weeks, doubling thereafter to a mean of 800 mL.
•The volume remained at this level until 40 weeks and then declined
by approximately 8 percent per week thereafter
•Although it is considered acceptable for an experienced examiner to
assess the amnionicfluid volume qualitatively, fluid is usually
assessed semiquantitatively(American Institute of Ultrasound in
Medicine, 2013a).
•Measurements include either the single deepest vertical fluid pocket
or the sum of the deepest vertical pockets from each of four equal
uterine quadrants—the amnionicfluid index
assess the amnionicfluid volume qualitatively, fluid is usually
assessed semiquantitatively(American Institute of Ultrasound in
Medicine, 2013a).
•Measurements include either the single deepest vertical fluid pocket
or the sum of the deepest vertical pockets from each of four equal
uterine quadrants—the amnionicfluid index
Single Deepest Pocket:
•This is also called the maximum vertical pocket.
•The ultrasound transducer is held perpendicular to the floor and
parallel to the long axis of the pregnant woman.
•In the sagittal plane, the largest vertical pocket of fluid is identified.
•The fluid pocket may contain fetal parts or loops of umbilical cord,
but these are not included in the measurement.
•The normal range for single deepest pocket that is most commonly
used is 2 to 8 cm, with values above and below this indicating
hydramnios and oligohydramnios, respectively.
•This is also called the maximum vertical pocket.
•The ultrasound transducer is held perpendicular to the floor and
parallel to the long axis of the pregnant woman.
•In the sagittal plane, the largest vertical pocket of fluid is identified.
•The fluid pocket may contain fetal parts or loops of umbilical cord,
but these are not included in the measurement.
•The normal range for single deepest pocket that is most commonly
used is 2 to 8 cm, with values above and below this indicating
hydramnios and oligohydramnios, respectively.
•The fetalbiophysical profile similarly uses a 2-cm single deepest
vertical pocket threshold to indicate a normal amnionicfluid volume
(American College of Obstetricians and Gynecologists, 2012).
•Single vertical pocket-------------------
vertical pocket threshold to indicate a normal amnionicfluid volume
(American College of Obstetricians and Gynecologists, 2012).
•Single vertical pocket-------------------
Measurment of AF
•Measurement of AFI-quantitative method of
measurement of amniotic fluid by usg. Single
largest pocket is measured in four quadrants
and added.
•Normal range is 5-24 cm
•Single deepest pocket
•Normal range is 2-8 cm
•Measurement of AFI-quantitative method of
measurement of amniotic fluid by usg. Single
largest pocket is measured in four quadrants
and added.
•Normal range is 5-24 cm
•Single deepest pocket
•Normal range is 2-8 cm
•Amnionic Fluid Index (AFI) -This was described by Phelan and
coworkers (1987) more than 25 years ago, and it remains one of the
most commonly used methods of amnionic fluid volume assessment.
•As with the single deepest fluid pocket measurement, the ultrasound
transducer is held perpendicular to the floor and parallel to the long
axis of the pregnant woman.
•The uterus is divided into four equal quadrants—the right-and left-
upper and lower quadrants, respectively.
•The AFI is the sum of the single deepest pocket from each quadrant.
coworkers (1987) more than 25 years ago, and it remains one of the
most commonly used methods of amnionic fluid volume assessment.
•As with the single deepest fluid pocket measurement, the ultrasound
transducer is held perpendicular to the floor and parallel to the long
axis of the pregnant woman.
•The uterus is divided into four equal quadrants—the right-and left-
upper and lower quadrants, respectively.
•The AFI is the sum of the single deepest pocket from each quadrant.
•A fluid pocket may contain fetal parts or umbilical cord loops, but
these are not included in the measurement.
•Color Doppler is generally used to verify that no umbilical cord is
included in the measurement.
•This may result in greater consistency and in reduction of
intraobserver variation(Callen, 2008; Hill, 2003).
•It has been reported, however, that color Doppler use results in a
lower AFI measurement, thus potentially leading to overdiagnosis of
oligohydramnios(Magann, 2001).
these are not included in the measurement.
•Color Doppler is generally used to verify that no umbilical cord is
included in the measurement.
•This may result in greater consistency and in reduction of
intraobserver variation(Callen, 2008; Hill, 2003).
•It has been reported, however, that color Doppler use results in a
lower AFI measurement, thus potentially leading to overdiagnosis of
oligohydramnios(Magann, 2001).
Measurement of amniotic fluid volume
•Amniotic fluid index
•Amniotic fluid index
Oligohydroamnios:
•This is an abnormally decreased amount of amnionic fluid.
•Oligohydramnios complicates approximately 1 to 2 percent of
pregnancies (Casey, 2000; Petrozella, 2011).
•Oligohydramnios is a cause for concern. When no measurable pocket
of amnionic fluid is identified, the term anhydramnios may be used.
•The sonographic diagnosis of oligohydramnios is usually based on an
AFI ≤ 5 cm or on a single deepest pocket of amnionic fluid ≤ 2 cm
(American College of Obstetricians and Gynecologists, 2012).
•This is an abnormally decreased amount of amnionic fluid.
•Oligohydramnios complicates approximately 1 to 2 percent of
pregnancies (Casey, 2000; Petrozella, 2011).
•Oligohydramnios is a cause for concern. When no measurable pocket
of amnionic fluid is identified, the term anhydramnios may be used.
•The sonographic diagnosis of oligohydramnios is usually based on an
AFI ≤ 5 cm or on a single deepest pocket of amnionic fluid ≤ 2 cm
(American College of Obstetricians and Gynecologists, 2012).
•The diagnosis also may be based on an AFI below the 5th or 2.5th
percentile determined by a gestational-age-specific nomogram. Or, it
may be based on subjective assessment of decreased amnionicfluid
volume.
•In the Moore nomogram, a threshold of 5 cm is below the 2.5th
percentile throughout the second and third trimesters
•When evaluating twin pregnancies for twintwintransfusion
syndrome, a single deepest pocket ≤ 2 cm is used to define
oligohydramnios(Society for Maternal-FetalMedicine, 2013).
percentile determined by a gestational-age-specific nomogram. Or, it
may be based on subjective assessment of decreased amnionicfluid
volume.
•In the Moore nomogram, a threshold of 5 cm is below the 2.5th
percentile throughout the second and third trimesters
•When evaluating twin pregnancies for twintwintransfusion
syndrome, a single deepest pocket ≤ 2 cm is used to define
oligohydramnios(Society for Maternal-FetalMedicine, 2013).
Causes:
•1-Preterm premature rapture of membrane: perhaps the most common
causes of oligohydramnios is PPROM.
•2-Post maturity.
•3-Placental insufficiency or intrauterine growth restriction.
•4-Fetal causes: a reduction in the production of amniotic fluid in the
second and third trimester is mediated primarily through a reduced or
absent fetal urine output.
•This is in turn is the consequence of an abnormality in fetal urinary tract
like:
•-Renal agenesis.
•-Bladder outlet obstruction.
•-Renal dysplasia
•-Polycystic or multicystic kidney disease.
•1-Preterm premature rapture of membrane: perhaps the most common
causes of oligohydramnios is PPROM.
•2-Post maturity.
•3-Placental insufficiency or intrauterine growth restriction.
•4-Fetal causes: a reduction in the production of amniotic fluid in the
second and third trimester is mediated primarily through a reduced or
absent fetal urine output.
•This is in turn is the consequence of an abnormality in fetal urinary tract
like:
•-Renal agenesis.
•-Bladder outlet obstruction.
•-Renal dysplasia
•-Polycystic or multicystic kidney disease.
•Fetal chromosomal anomalies
•Intrauterine infections
•Drugs-PG inhibitors, ACE inhibitors
•IUGR associated with placental insufficency
•Amnion nodosum-failure of secretion by the cells of the amnion
•Intrauterine infections
•Drugs-PG inhibitors, ACE inhibitors
•IUGR associated with placental insufficency
•Amnion nodosum-failure of secretion by the cells of the amnion
Oligohydramnios-causes
▪Fetal
▫Chromosomal anomalies
▫Congenital abnormalities
▫Growth restriction
▫Demise
▫Post-term pregnancy
▫Ruptured membranes
▪Placental
▫Abruption
▫TTTS
▪Maternal
▫Uteroplacental insufficiency
▫Hypertension
▫Pre-ecclampsia
▫Diabetes
▪Iatrogenic
▫PG synthesis inhibitors
▫ACE inhibitors
▪Idiopathic
▪Fetal
▫Chromosomal anomalies
▫Congenital abnormalities
▫Growth restriction
▫Demise
▫Post-term pregnancy
▫Ruptured membranes
▪Placental
▫Abruption
▫TTTS
▪Maternal
▫Uteroplacental insufficiency
▫Hypertension
▫Pre-ecclampsia
▫Diabetes
▪Iatrogenic
▫PG synthesis inhibitors
▫ACE inhibitors
▪Idiopathic
Early-Onset Oligohydramnios:
•When amnionicfluid volume is abnormally decreased from the early
second trimester, it may reflect a fetalabnormality that precludes
normal urination, or it may represent a placental abnormality severe
enough to impair perfusion.
•In either circumstance, the prognosis is poor.
•Second-trimester rupture of the fetalmembranes may result in
oligohydramnios—and should be excluded.
•When amnionicfluid volume is abnormally decreased from the early
second trimester, it may reflect a fetalabnormality that precludes
normal urination, or it may represent a placental abnormality severe
enough to impair perfusion.
•In either circumstance, the prognosis is poor.
•Second-trimester rupture of the fetalmembranes may result in
oligohydramnios—and should be excluded.
Oligohydramnios after Midpregnancy:
•When amnionic fluid volume becomes abnormally decreased in the late
second or in the third trimester, it more likely is associated with fetal-
growth restriction, a placental abnormality, or a maternal complication
such as preeclampsia or vascular disease.
•Underlying etiology is often presumed to be uteroplacental insufficiency,
which can impair fetal growth and reduce fetal urine output.
•Investigation of third-trimester oligohydramnios generally includes
evaluation for membrane rupture and sonography to assess growth.
•When amnionic fluid volume becomes abnormally decreased in the late
second or in the third trimester, it more likely is associated with fetal-
growth restriction, a placental abnormality, or a maternal complication
such as preeclampsia or vascular disease.
•Underlying etiology is often presumed to be uteroplacental insufficiency,
which can impair fetal growth and reduce fetal urine output.
•Investigation of third-trimester oligohydramnios generally includes
evaluation for membrane rupture and sonography to assess growth.
Post term:
•Trimmer and coworkers (1990) sonographically measured hourly fetal
urine production using sequential bladder volume measurements in 38
pregnancies of ≥ 42 weeks.
•Diminished urine production was found to be associated with
oligohydramnios.
•They hypothesized that decreased fetal urine flow was likely the result of
preexisting oligohydramnios that limited fetal swallowing.
•Oz and associates (2002), using Doppler waveforms, concluded that fetal
renal blood flow is reduced in those postterm pregnancies complicated by
oligohydramnios.
•Trimmer and coworkers (1990) sonographically measured hourly fetal
urine production using sequential bladder volume measurements in 38
pregnancies of ≥ 42 weeks.
•Diminished urine production was found to be associated with
oligohydramnios.
•They hypothesized that decreased fetal urine flow was likely the result of
preexisting oligohydramnios that limited fetal swallowing.
•Oz and associates (2002), using Doppler waveforms, concluded that fetal
renal blood flow is reduced in those postterm pregnancies complicated by
oligohydramnios.
Congenital Anomalies:
•Decreased amnionic fluid volume beginning early in gestation are
secondary to genitourinary anomalies.
•Anomalies of other organ systems, aneuploidy, and other genetic
syndromes also have the potential to cause oligohydramnios
indirectly, either from fetal decompensation, fetalgrowth restriction,
or an accompanying placental abnormality.
•Overall, approximately 3 percent of newborns with congenital
anomalies have oligohydramnios found during prenatal sonography
(Martinez-Frias, 1999).
•Decreased amnionic fluid volume beginning early in gestation are
secondary to genitourinary anomalies.
•Anomalies of other organ systems, aneuploidy, and other genetic
syndromes also have the potential to cause oligohydramnios
indirectly, either from fetal decompensation, fetalgrowth restriction,
or an accompanying placental abnormality.
•Overall, approximately 3 percent of newborns with congenital
anomalies have oligohydramnios found during prenatal sonography
(Martinez-Frias, 1999).
Congenital anomalies associated with oligohydramnios
•Amnionicband syndrome
•Cardiac
•Fallotstetralogy
•Septaldefects
•CNS
•Holoprosencephaly
•Meningocele
•Encephalocele
•microcephaly
•Cloacaldysgenesis
•Chromosomal
•Triploidy
•Trisomy18
•Turner syndrome
•Cystic hygroma
•Diaphragmatic hernia
•Genitourinary
•Renal dysgenesis/aplasia
•Urethral obstruction
•Bladder exystrophy
•Meckelgrubersyndrome
•Uretro-pelvic junction obstruction
•Prune belly syndrome
•Hypothyroidism
•Skeletal
•TRAP sequence
•TTTS
•Amnionicband syndrome
•Cardiac
•Fallotstetralogy
•Septaldefects
•CNS
•Holoprosencephaly
•Meningocele
•Encephalocele
•microcephaly
•Cloacaldysgenesis
•Chromosomal
•Triploidy
•Trisomy18
•Turner syndrome
•Cystic hygroma
•Diaphragmatic hernia
•Genitourinary
•Renal dysgenesis/aplasia
•Urethral obstruction
•Bladder exystrophy
•Meckelgrubersyndrome
•Uretro-pelvic junction obstruction
•Prune belly syndrome
•Hypothyroidism
•Skeletal
•TRAP sequence
•TTTS
•Selected renal abnormalities that lead to absent fetal urine production
include :
•Bilateral renal agenesis
•Bilateral multicystic dysplastic kidney,
•unilateral renal agenesis with contralateral multicystic dysplastic kidney,
•Infantile form of autosomal recessive polycystic kidney disease.
•Fetal bladder outlet obstruction
--Posterior urethral valves,
--urethral atresia or stenosis, or the megacystis
•Microcolon intestinal hypoperistalsis syndrome.
•Complex fetal genitourinary abnormalities such as persistent cloaca and
sirenomelia
include :
•Bilateral renal agenesis
•Bilateral multicystic dysplastic kidney,
•unilateral renal agenesis with contralateral multicystic dysplastic kidney,
•Infantile form of autosomal recessive polycystic kidney disease.
•Fetal bladder outlet obstruction
--Posterior urethral valves,
--urethral atresia or stenosis, or the megacystis
•Microcolon intestinal hypoperistalsis syndrome.
•Complex fetal genitourinary abnormalities such as persistent cloaca and
sirenomelia
Medication:
•Oligohydramnios has been associated with exposure to drugs that
block the renin-angiotensin system.
•These include angiotensin-converting enzyme (ACE) inhibitors and
nonsteroidal antiinflammatory drugs (NSAIDs). When taken in the
second, third trimester, ACE inhibitors and angiotensin-receptor
blockers may create fetal hypotension, renal hypoperfusion.
•NSAIDs have been associated with decreased fetal urine production.
In neonates, their use may result in acute and chronic renal
insufficiency (Fanos, 2011).
•Oligohydramnios has been associated with exposure to drugs that
block the renin-angiotensin system.
•These include angiotensin-converting enzyme (ACE) inhibitors and
nonsteroidal antiinflammatory drugs (NSAIDs). When taken in the
second, third trimester, ACE inhibitors and angiotensin-receptor
blockers may create fetal hypotension, renal hypoperfusion.
•NSAIDs have been associated with decreased fetal urine production.
In neonates, their use may result in acute and chronic renal
insufficiency (Fanos, 2011).
Oligohydramnioscomplication
▪MidtrimesterPROM often leads to pulmonary hypoplasia, fetal
compression syndrome, and amniotic band syndrome.
▪Oligohydramniosis a frequent finding in pregnancies involving IUGR
and is most likely secondary to decreased fetalblood volume, renal
blood flow, and, subsequently, fetalurine output.
▪AFV is an important predictor of fetalwell-being in pregnancies
beyond 40 weeks' gestation
▪AFV is a predictor of the fetaltolerance of labor,
▪MidtrimesterPROM often leads to pulmonary hypoplasia, fetal
compression syndrome, and amniotic band syndrome.
▪Oligohydramniosis a frequent finding in pregnancies involving IUGR
and is most likely secondary to decreased fetalblood volume, renal
blood flow, and, subsequently, fetalurine output.
▪AFV is an important predictor of fetalwell-being in pregnancies
beyond 40 weeks' gestation
▪AFV is a predictor of the fetaltolerance of labor,
Vascular tone is an essential target of the paracrine and endocrine
regulations during pregnancy.
The lowering of arteriolar tonicityprecedes blood volume expansion
and seems to be the primary step in the physiological hemodynamic
modifications.
Poor placentation may be expressed in the persistence of high
impedance in the uteroplacentalcirculation
-assessed by the second trimester Doppler in the uterine vessels,
represents a powerful predisposing factor to
IUGR
Oligohydramnios
Preeclampsia
regulations during pregnancy.
The lowering of arteriolar tonicityprecedes blood volume expansion
and seems to be the primary step in the physiological hemodynamic
modifications.
Poor placentation may be expressed in the persistence of high
impedance in the uteroplacentalcirculation
-assessed by the second trimester Doppler in the uterine vessels,
represents a powerful predisposing factor to
IUGR
Oligohydramnios
Preeclampsia
•If there is bilateral renal agenesis, no urine is produced, and the
resulting anhydramniosleads to limb contractures, a distinctively
compressed face, and death from pulmonary hypoplasia
•When this combination of abnormalities results from renal agenesis,
it is called Potter syndrome, after Dr. Edith Potter, who described it in
1946.
•When this constellation stems from another etiologyof decreased
amnionicfluid volume, it is generally called Potter sequence.
resulting anhydramniosleads to limb contractures, a distinctively
compressed face, and death from pulmonary hypoplasia
•When this combination of abnormalities results from renal agenesis,
it is called Potter syndrome, after Dr. Edith Potter, who described it in
1946.
•When this constellation stems from another etiologyof decreased
amnionicfluid volume, it is generally called Potter sequence.
Normal-sized lungs (top) are shown in comparison
with hypoplasticlungs (bottom) of fetusesat the same gestational
age. (From Newbould, 1994, with permission)
with hypoplasticlungs (bottom) of fetusesat the same gestational
age. (From Newbould, 1994, with permission)
Pulmonary Hypoplasia:
•When decreased amnionicfluid is first identified before the
midsecondtrimester, particularly before 20 to 22 weeks, pulmonary
hypoplasiais a significant concern.
•The underlying etiologyis a major factor in the prognosis for such
pregnancies.
•Severe oligohydramniossecondary to a renal abnormality generally
has a lethal prognosis.
•If a placental hematoma or chronic abruption is severe enough to
result in oligohydramnios—the chronic abruption-oligohydramnios
sequence—it commonly also causes growth restriction.
•The prognosis for this constellation is similarly poor.
•When decreased amnionicfluid is first identified before the
midsecondtrimester, particularly before 20 to 22 weeks, pulmonary
hypoplasiais a significant concern.
•The underlying etiologyis a major factor in the prognosis for such
pregnancies.
•Severe oligohydramniossecondary to a renal abnormality generally
has a lethal prognosis.
•If a placental hematoma or chronic abruption is severe enough to
result in oligohydramnios—the chronic abruption-oligohydramnios
sequence—it commonly also causes growth restriction.
•The prognosis for this constellation is similarly poor.
•“Borderline” Oligohydramnios
•The term borderline AFI or borderline oligohydramniosis somewhat
controversial. It usually refers to AFIs between 5 and 8 cm (Baron,
1995; Magann, 2011; Petrozella, 2011).
•Through the mid-third trimester, an AFI value of 8 cm is below the
5th percentile on the Moore nomogram
•Petrozellaand colleagues (2011) found that pregnancies between 24
and 34 weeks with an AFI between 5 and 8 cm were not more likely
than those with an AFI above 8 cm to be complicated by maternal
hypertension, stillbirth, or neonatal death
•The term borderline AFI or borderline oligohydramniosis somewhat
controversial. It usually refers to AFIs between 5 and 8 cm (Baron,
1995; Magann, 2011; Petrozella, 2011).
•Through the mid-third trimester, an AFI value of 8 cm is below the
5th percentile on the Moore nomogram
•Petrozellaand colleagues (2011) found that pregnancies between 24
and 34 weeks with an AFI between 5 and 8 cm were not more likely
than those with an AFI above 8 cm to be complicated by maternal
hypertension, stillbirth, or neonatal death
Pregnancy Outcomes
•Casey and colleagues (2000) found that an AFI ≤ 5 cm complicated 2
percent of pregnancies higher rates of fetalstillbirth, growth
restriction, nonreassuringheart rate pattern, and meconium
aspiration syndrome were noted.
•Petrozellaand associates(2011) similarly reported that with an AFI ≤ 5
cm identified between 24 and 34 weeks, there was increased risk for
stillbirth, spontaneous or medically indicated preterm birth, heart
rate pattern abnormalities, and growth restriction.
•Casey and colleagues (2000) found that an AFI ≤ 5 cm complicated 2
percent of pregnancies higher rates of fetalstillbirth, growth
restriction, nonreassuringheart rate pattern, and meconium
aspiration syndrome were noted.
•Petrozellaand associates(2011) similarly reported that with an AFI ≤ 5
cm identified between 24 and 34 weeks, there was increased risk for
stillbirth, spontaneous or medically indicated preterm birth, heart
rate pattern abnormalities, and growth restriction.
•Chauhan and coworkers (1999) found that women with
oligohydramnios had a twofold increased risk for cesarean delivery
for fetal distress and a fivefold risk for an Apgar score < 7 at 5
minutes compared with pregnancies with normal AFI.
oligohydramnios had a twofold increased risk for cesarean delivery
for fetal distress and a fivefold risk for an Apgar score < 7 at 5
minutes compared with pregnancies with normal AFI.
Diagnosis:
1)Uterine size is much smaller than the period of amenorrhea
2)Less fetalmovements
3)The uterus is “full of fetus” because of scanty liquor
4)Malpresentation(breech) is common
5)Evidences of intrauterine growth retardation of the fetus
6)Sonographicdiagnosis is made when largest liquor pool is less
than 2 cm. Ultrasound visualization is done following
amnioinfusionof 300 ml of warm saline solution
7)Visualization of normal filling and emptying of fetalbladder
essentially rules out urinary tract abnormality.
8)Oligohydramnioswith fetalsymmetric growth restriction is
associated with increased chromosomal abnormalities.
1)Uterine size is much smaller than the period of amenorrhea
2)Less fetalmovements
3)The uterus is “full of fetus” because of scanty liquor
4)Malpresentation(breech) is common
5)Evidences of intrauterine growth retardation of the fetus
6)Sonographicdiagnosis is made when largest liquor pool is less
than 2 cm. Ultrasound visualization is done following
amnioinfusionof 300 ml of warm saline solution
7)Visualization of normal filling and emptying of fetalbladder
essentially rules out urinary tract abnormality.
8)Oligohydramnioswith fetalsymmetric growth restriction is
associated with increased chromosomal abnormalities.
Dr Mona Shroff
www.obgyntoday.info
*
www.obgyntoday.info
*
Management
●ADEQUATE REST –decreases dehydration
●HYDRATION –Oral/IV Hypotonic fluids(2 Lit/d)
temperoryincrease
helpful during labour,prior
to ECV, USG
●SERIAL USG –Monitor growth,AFI,BPP
●INDUCTION OF LABOUR/ LSCS
Lung maturity attained
Lethal malformation
Fetal jeopardy
SevIUGR
Severe oligo
●DDAVP: ? Research settings
●ADEQUATE REST –decreases dehydration
●HYDRATION –Oral/IV Hypotonic fluids(2 Lit/d)
temperoryincrease
helpful during labour,prior
to ECV, USG
●SERIAL USG –Monitor growth,AFI,BPP
●INDUCTION OF LABOUR/ LSCS
Lung maturity attained
Lethal malformation
Fetal jeopardy
SevIUGR
Severe oligo
●DDAVP: ? Research settings
●
●AMNIOINFUSION
INDICATIONS
1.Diagnostic
2.Prophylactic
3.Therapeutic
*
●AMNIOINFUSION
INDICATIONS
1.Diagnostic
2.Prophylactic
3.Therapeutic
*
AMNIOINFUSION:
•Transvaginalamnioinfusionhas been extended into three clinical
areas.
•These include:
•(1) treatment of variable or prolonged decelerations,
•(2) prophylaxis for women with oligohydramnios, as with prolonged
ruptured membranes, and
•(3) attempts to dilute or wash out thick
meconium
•Transvaginalamnioinfusionhas been extended into three clinical
areas.
•These include:
•(1) treatment of variable or prolonged decelerations,
•(2) prophylaxis for women with oligohydramnios, as with prolonged
ruptured membranes, and
•(3) attempts to dilute or wash out thick
meconium
•Many different amnioinfusionprotocols have been reported, but
most include a 500-to 800-mL bolus of warmed normal saline
followed by a continuous infusion of approximately 3 Ml per minute
(Owen, 1990; Pressman, 1996).
•In another study, Rinehart and colleagues (2000) randomly gave a
500-mL bolus of normal saline at room temperature alone or 500-mL
bolus plus continuous infusion of 3 mLper minute.
most include a 500-to 800-mL bolus of warmed normal saline
followed by a continuous infusion of approximately 3 Ml per minute
(Owen, 1990; Pressman, 1996).
•In another study, Rinehart and colleagues (2000) randomly gave a
500-mL bolus of normal saline at room temperature alone or 500-mL
bolus plus continuous infusion of 3 mLper minute.
Prophylactic Amnioinfusionfor Variable
Decelerations:
•Hofmeyrand Lawrie(2012) used the Cochrane Database to
specifically analyze the effects of amnioinfusionin the management
of fetalheart rate patterns associated with umbilical cord
compression.
•Nineteen suitable studies were identified, most with fewer than 200
participants.
•It was concluded that amnioinfusionappeared to be useful in
reducing the occurrence of variable decelerations, improving
neonatal outcome, and reducing cesareandelivery rates.
•The American College of Obstetricians and Gynecologists(2013a)
recommends consideration of amnioinfusionwith persistent variable
decelerations.
Decelerations:
•Hofmeyrand Lawrie(2012) used the Cochrane Database to
specifically analyze the effects of amnioinfusionin the management
of fetalheart rate patterns associated with umbilical cord
compression.
•Nineteen suitable studies were identified, most with fewer than 200
participants.
•It was concluded that amnioinfusionappeared to be useful in
reducing the occurrence of variable decelerations, improving
neonatal outcome, and reducing cesareandelivery rates.
•The American College of Obstetricians and Gynecologists(2013a)
recommends consideration of amnioinfusionwith persistent variable
decelerations.
Prophylactic Amnioinfusionfor Oligohydramnios
•Amnioinfusionin women with oligohydramnioshas been used
prophylacticallyto avoid intrapartumfetalheart rate patterns from
cord occlusion.
•Nageotteand coworkers(1991) found that this resulted in
significantly decreased frequency and severity of variable
decelerations in labor.
•However, the cesareandelivery rate or condition of term infants was
not improved. In a randomized investigation, Macriand colleagues
(1992) studied prophylactic amnioinfusionin 170 term and postterm
pregnancies complicated by both thick meconiuand
oligohydramnios.
•Amnioinfusionin women with oligohydramnioshas been used
prophylacticallyto avoid intrapartumfetalheart rate patterns from
cord occlusion.
•Nageotteand coworkers(1991) found that this resulted in
significantly decreased frequency and severity of variable
decelerations in labor.
•However, the cesareandelivery rate or condition of term infants was
not improved. In a randomized investigation, Macriand colleagues
(1992) studied prophylactic amnioinfusionin 170 term and postterm
pregnancies complicated by both thick meconiuand
oligohydramnios.
•Amnioinfusionsignificantly reduced cesareandelivery rates for fetal
distress and meconiumaspiration syndrome. In contrast, Ogundipe
and associates (1994) randomly assigned 116 term pregnancies with
an amnionicfluid index < 5 cm to receive prophylactic amnioinfusion
or standard obstetrical care.
•There were no significant differences in overall cesareandelivery
rates, delivery rates for fetaldistress, or umbilical cord acid-base
studies.
distress and meconiumaspiration syndrome. In contrast, Ogundipe
and associates (1994) randomly assigned 116 term pregnancies with
an amnionicfluid index < 5 cm to receive prophylactic amnioinfusion
or standard obstetrical care.
•There were no significant differences in overall cesareandelivery
rates, delivery rates for fetaldistress, or umbilical cord acid-base
studies.
Amnioinfusionfor Meconium-Stained AmnionicFluid
•Pierce and associates (2000) summarized the results of 13
prospective trials of intrapartumamnioinfusionin 1924 women with
moderate to thick meconium-stained fluid.
•Infants born to women treated by amnioinfusionwere significantly
less likely to have meconiumbelow the vocal cords and were less
likely to develop meconiumaspiration syndrome than infants born to
women not undergoing amnioinfusion.
•The cesareandelivery rate was also lower in the amnioinfusion
group.
•Pierce and associates (2000) summarized the results of 13
prospective trials of intrapartumamnioinfusionin 1924 women with
moderate to thick meconium-stained fluid.
•Infants born to women treated by amnioinfusionwere significantly
less likely to have meconiumbelow the vocal cords and were less
likely to develop meconiumaspiration syndrome than infants born to
women not undergoing amnioinfusion.
•The cesareandelivery rate was also lower in the amnioinfusion
group.
•Last, Fraser and colleagues (2005) randomized amnioinfusionin 1998
women with thick meconiumstaining of the amnionicfluid in labor
and found no benefits.
•Because of these findings, the American College of Obstetricians and
Gynecologists(2012a, 2013c) does not recommend amnioinfusionto
dilute meconium-stained amnionicfluid.
•According to Xuand coworkers(2007), in areas lacking continuous
monitoring, amnioinfusionmay be used to lower the incidence of
meconiumaspiration syndrome.
women with thick meconiumstaining of the amnionicfluid in labor
and found no benefits.
•Because of these findings, the American College of Obstetricians and
Gynecologists(2012a, 2013c) does not recommend amnioinfusionto
dilute meconium-stained amnionicfluid.
•According to Xuand coworkers(2007), in areas lacking continuous
monitoring, amnioinfusionmay be used to lower the incidence of
meconiumaspiration syndrome.
•HofmeyrGJ. Prophylactic versus therapeutic amnioinfusion
for oligohydramniosin labour. Cochrane Database of
Systematic Reviews1996,Issue concludes
•There appears to be no advantage of prophylactic
amnioinfusionover therapeutic amnioinfusioncarried out
only when fetal heart rate decelerations or thick meconium-
staining of the liquor occur.
for oligohydramniosin labour. Cochrane Database of
Systematic Reviews1996,Issue concludes
•There appears to be no advantage of prophylactic
amnioinfusionover therapeutic amnioinfusioncarried out
only when fetal heart rate decelerations or thick meconium-
staining of the liquor occur.
Complications Associated with Amnioinfusion
from a Survey of 186 Obstetrical Units
•Uterine hypertonus-------------------------------27 (14)
•Abnormal fetalheart rate tracing ---------------17 (9)
•Chorioamnionitis---------------------------------------7 (4)
•Cord prolapse-------------------------------------------5 (2)
•Uterine rupture----------------------------------------4 (2)
•Maternal cardiac or respiratory-compromise---3 (2)
•Placental abruption-----------------------------------2 (1)
•Maternal death----------------------------------------2 (1)
from a Survey of 186 Obstetrical Units
•Uterine hypertonus-------------------------------27 (14)
•Abnormal fetalheart rate tracing ---------------17 (9)
•Chorioamnionitis---------------------------------------7 (4)
•Cord prolapse-------------------------------------------5 (2)
•Uterine rupture----------------------------------------4 (2)
•Maternal cardiac or respiratory-compromise---3 (2)
•Placental abruption-----------------------------------2 (1)
•Maternal death----------------------------------------2 (1)
●Oral hydration + DDAVP : Prevents diuresis
●Results in maternal plasma hypotonicity–-fetal plasma
hypotonicity—increased fetal urine production—reduced
fetal swallowing—increased AFI
●Results in maternal plasma hypotonicity–-fetal plasma
hypotonicity—increased fetal urine production—reduced
fetal swallowing—increased AFI
TREATMENT ACC. TO CAUSE
●Drug induced –OMIT DRUG
●PROM –INDUCTION
●PPROM –Antibiotics,steroid–Induction
●FETAL SURGERY
VESICO AMNIOTIC SHUNT-PUV
Laser photocoagulation for TTTS
●Drug induced –OMIT DRUG
●PROM –INDUCTION
●PPROM –Antibiotics,steroid–Induction
●FETAL SURGERY
VESICO AMNIOTIC SHUNT-PUV
Laser photocoagulation for TTTS
Posterior urethral valves
●Sonographic findings:
●Keyhole sign
●Sonographic findings:
●Keyhole sign
Posterior urethral valves
●Management:
●Karyotyping
●Perform serial bladder drainage every 3-4 days
●Use sample of 3
rd
drainage
●Isotonic urine indicate poor function
●Management:
●Karyotyping
●Perform serial bladder drainage every 3-4 days
●Use sample of 3
rd
drainage
●Isotonic urine indicate poor function
Posterior urethral valves
●Good prognostic biochemical markers:
●Na < 100meq/L
●Cl < 90meq/L
●Osmolarity <210mOsm/L
●B2 microglobulin < 4mg/L
●Ca < 8mg/dl
●Indication for vesico amniotic shunts
●Good prognostic biochemical markers:
●Na < 100meq/L
●Cl < 90meq/L
●Osmolarity <210mOsm/L
●B2 microglobulin < 4mg/L
●Ca < 8mg/dl
●Indication for vesico amniotic shunts
*
L –Arginine
•L-arginine is a versatile amino acid with a wide range of biological
functions.
•It serves as a precursor not only
to proteins but also nitric oxide which has been identified as endothelium-
derived relaxing factor.
Palmer RM, Ashton DS, MoncadaS. Vascular endothelial cells synthesize nitric oxide from L-arginine.
Nature 1999;333:664-6.
•L-arginine is a versatile amino acid with a wide range of biological
functions.
•It serves as a precursor not only
to proteins but also nitric oxide which has been identified as endothelium-
derived relaxing factor.
Palmer RM, Ashton DS, MoncadaS. Vascular endothelial cells synthesize nitric oxide from L-arginine.
Nature 1999;333:664-6.
Act by…
•L-arginineincreases uteroplacentalblood flow through nitric oxide
mediated dilatation of vessels thereby increasing the supply of nutrients to
the fetus aiding its growth.
•L-Arginine improves Uteroplacentalblood flow to overcome placental
ischemia by increasing Nitric oxide.
•This results in vasodilation of uterine arteries.
•L-arginineincreases uteroplacentalblood flow through nitric oxide
mediated dilatation of vessels thereby increasing the supply of nutrients to
the fetus aiding its growth.
•L-Arginine improves Uteroplacentalblood flow to overcome placental
ischemia by increasing Nitric oxide.
•This results in vasodilation of uterine arteries.
Rytlewskiet al. studied the influence of oral supplementation with low dose of ARG on
•biophysical profile,
•Oligohydramnios,
•feto-placental circulation and
•neonatal outcome in preeclampsia.
•This was a randomized, placebo-controlled, double-blind, clinical trial.
Oral therapy with 3 g of Arginine daily or placebo was given as a supplement to standard
therapy.
•The results
-L arginine treatment accelerated fetal weight gain and
-improved biophysical profile.
•Starting from the 3rd week of therapy,
-the umbilical artery pulsatilityindices values were significantly lower in the ARG group.
-Neonates in this group revealed higher Apgar scores.
•biophysical profile,
•Oligohydramnios,
•feto-placental circulation and
•neonatal outcome in preeclampsia.
•This was a randomized, placebo-controlled, double-blind, clinical trial.
Oral therapy with 3 g of Arginine daily or placebo was given as a supplement to standard
therapy.
•The results
-L arginine treatment accelerated fetal weight gain and
-improved biophysical profile.
•Starting from the 3rd week of therapy,
-the umbilical artery pulsatilityindices values were significantly lower in the ARG group.
-Neonates in this group revealed higher Apgar scores.
The authors concluded that supplementary treatment with oral ARG seems
to be
promising in improving
-foetalwell-being
-neonatal outcome
-prolonging pregnancy complicated with pre-eclampsia & Oligohydramnios.
to be
promising in improving
-foetalwell-being
-neonatal outcome
-prolonging pregnancy complicated with pre-eclampsia & Oligohydramnios.
Polyhydramnios
Definition :
It means excessive amniotic fluid, more than 2 liters. By ultrasound the
vertical diameter of the largest pocket of amniotic fluid measure 8 cm or
more, or the amniotic fluid index (AFI) is 25 cm or more.
It can be classified into :
1-Mild single deepest pocket 8 –9.9 c.m./AFI is 25 to 29.9 cm
2-Moderate : single deepest pocket 10 -11.9 c.m./30 to 34.9 cm
3-Severe : single deepest pocket ≥ 12 c.m./35 cm or more
Incidence : 1 –2 % of all pregnancies.
Definition :
It means excessive amniotic fluid, more than 2 liters. By ultrasound the
vertical diameter of the largest pocket of amniotic fluid measure 8 cm or
more, or the amniotic fluid index (AFI) is 25 cm or more.
It can be classified into :
1-Mild single deepest pocket 8 –9.9 c.m./AFI is 25 to 29.9 cm
2-Moderate : single deepest pocket 10 -11.9 c.m./30 to 34.9 cm
3-Severe : single deepest pocket ≥ 12 c.m./35 cm or more
Incidence : 1 –2 % of all pregnancies.
•Mild hydramniosis the most common, comprising approximately
two thirds of cases.
•Moderate hydramniosaccounts for about 20 percent, and severe
hydramniosapproximately 15 percent.
two thirds of cases.
•Moderate hydramniosaccounts for about 20 percent, and severe
hydramniosapproximately 15 percent.
•Common underlying causes of hydramniosinclude fetalcongenital
anomalies in approximately 15 percent and diabetes in 15 to 20
percent
•Congenital infection and red blood cell alloimmunizationare less
frequent reasons.
•Infections that may present with hydramniosinclude
cytomegalovirus, toxoplasmosis, syphilis, and parvovirus
anomalies in approximately 15 percent and diabetes in 15 to 20
percent
•Congenital infection and red blood cell alloimmunizationare less
frequent reasons.
•Infections that may present with hydramniosinclude
cytomegalovirus, toxoplasmosis, syphilis, and parvovirus
•Hydramniosis often a component of hydropsfetalis, and several of
the above etiologies—selected anomalies, infections, and
alloimmunization—may result in a hydropicfetusand placenta.
•The underlying pathophysiologyin such cases is complex but is
frequently related to a high cardiac-output state.
•Severe fetalanemiais the classic example. Because the etiologiesof
hydramniosare so varied, hydramniostreatment also varies and is
tailored in most cases to the underlying cause.
the above etiologies—selected anomalies, infections, and
alloimmunization—may result in a hydropicfetusand placenta.
•The underlying pathophysiologyin such cases is complex but is
frequently related to a high cardiac-output state.
•Severe fetalanemiais the classic example. Because the etiologiesof
hydramniosare so varied, hydramniostreatment also varies and is
tailored in most cases to the underlying cause.
Diabetes Mellitus
•The amnionicfluid glucose concentration is higher in diabetic women
than in those without diabetes, and the amnionicfluid index may
correlate with the amnionicfluid glucose concentration(Dashe, 2000;
Spellacy, 1973; Weiss, 1985).
•Such findings support the hypothesis that maternal hyperglycemia
causes fetalhyperglycemia, with resulting fetalosmotic diuresisinto
the amnionicfluid compartment.
•The amnionicfluid glucose concentration is higher in diabetic women
than in those without diabetes, and the amnionicfluid index may
correlate with the amnionicfluid glucose concentration(Dashe, 2000;
Spellacy, 1973; Weiss, 1985).
•Such findings support the hypothesis that maternal hyperglycemia
causes fetalhyperglycemia, with resulting fetalosmotic diuresisinto
the amnionicfluid compartment.
Congenital Anomalies
•Severe central nervous system abnormalities, such as anencephaly,
hydranencephaly, or holoprosencephaly, can result in hydramnios
due to impaired fetalswallowing.
•Fetalneuromuscular disorders such as myotonicdystrophy also may
lead to excessive amnionicfluid.
•Obstruction of the fetalupper gastrointestinal tract—esophagealor
duodenal atresia—is often associated with hydramnios.
•Severe central nervous system abnormalities, such as anencephaly,
hydranencephaly, or holoprosencephaly, can result in hydramnios
due to impaired fetalswallowing.
•Fetalneuromuscular disorders such as myotonicdystrophy also may
lead to excessive amnionicfluid.
•Obstruction of the fetalupper gastrointestinal tract—esophagealor
duodenal atresia—is often associated with hydramnios.
•Other obstructive causes include clefts, micrognathia, congenital
high-airway obstruction sequence, and fetalneck masses.
•Severe fetalthoracic abnormalities, such as diaphragmatic hernia,
cystic adenomatoidmalformation, and pulmonary sequestration,
may be associated with hydramniosdue to mediastinalshift and
impaired swallowing, occasionally with development of hydrops.
•A common fetalrenal anomaly, ureteropelvicjunction obstruction,
may at times result in paradoxical hydramnios.
high-airway obstruction sequence, and fetalneck masses.
•Severe fetalthoracic abnormalities, such as diaphragmatic hernia,
cystic adenomatoidmalformation, and pulmonary sequestration,
may be associated with hydramniosdue to mediastinalshift and
impaired swallowing, occasionally with development of hydrops.
•A common fetalrenal anomaly, ureteropelvicjunction obstruction,
may at times result in paradoxical hydramnios.
•And although rare, tumorssuch as fetalsacrococcygealteratoma,
fetalmesoblasticnephroma, and large placental chorioangiomasare
frequently accompanied by abnormally increased amnionicfluid
volume.
•If a fetalabnormality is encountered concurrent with hydramnios,
amniocentesis should be considered, because the aneuploidyrisk is
significantly increased(Dashe, 2002; Pri-Paz, 2012).
fetalmesoblasticnephroma, and large placental chorioangiomasare
frequently accompanied by abnormally increased amnionicfluid
volume.
•If a fetalabnormality is encountered concurrent with hydramnios,
amniocentesis should be considered, because the aneuploidyrisk is
significantly increased(Dashe, 2002; Pri-Paz, 2012).
•Hydramniosis generally defined in multifetalgestations as a single
deepest amnionicfluid pocket measuring 8 cm or more.
•It may be further characterized as moderate if the single deepest
pocket is at least 10 cm and severe if this pocket is at least 12 cm.
•In monochorionicpregnancies, hydramniosof one sac and
oligohydramniosof the other are diagnostic criteria for twintwin
transfusion syndrome,
deepest amnionicfluid pocket measuring 8 cm or more.
•It may be further characterized as moderate if the single deepest
pocket is at least 10 cm and severe if this pocket is at least 12 cm.
•In monochorionicpregnancies, hydramniosof one sac and
oligohydramniosof the other are diagnostic criteria for twintwin
transfusion syndrome,
Polyhydramnioscauses:
▪Maternal hyperglycemia
▪GIT anomalies(obstructive)
▫Esophagealatresia
▫Tracheoesophagealfistula
▫Duodenal atresia
▪Nonimmunehydrops
▪CNS anomalies
▫Anencephaly
▫Open spinabifida
▪Thoracic malformations
▫Diaphragmatic hernia
▪Congenital infections
▫Syphilis, hepatitis
▪Chromosomal anomalies
▪High output Cardiac failure
▫Fetalanemia
▫Sacrococcygealteratoma
▫chorioangioma
▪Fetalpolyuria
▫Fetalpseudohyperaldosteronism
▫Fetalbartter
▫Nephrogenicdiabetes insipidus
▪Placental chorioangioma
▪Maternal substance abuse
▪Maternal hyperglycemia
▪GIT anomalies(obstructive)
▫Esophagealatresia
▫Tracheoesophagealfistula
▫Duodenal atresia
▪Nonimmunehydrops
▪CNS anomalies
▫Anencephaly
▫Open spinabifida
▪Thoracic malformations
▫Diaphragmatic hernia
▪Congenital infections
▫Syphilis, hepatitis
▪Chromosomal anomalies
▪High output Cardiac failure
▫Fetalanemia
▫Sacrococcygealteratoma
▫chorioangioma
▪Fetalpolyuria
▫Fetalpseudohyperaldosteronism
▫Fetalbartter
▫Nephrogenicdiabetes insipidus
▪Placental chorioangioma
▪Maternal substance abuse
CLINICAL TYPES:
•Depending on the rapidity of onset, hydramniosmay be:
•(a) Chronic (mostcommon) —onset is insidious taking few weeks.
•(b) Acute (extremely rare) —onset is sudden, within few days or
may appear acutely on pre-existing chronic variety.
•The chronic variety is 10 times commoner than the acute one.
•Depending on the rapidity of onset, hydramniosmay be:
•(a) Chronic (mostcommon) —onset is insidious taking few weeks.
•(b) Acute (extremely rare) —onset is sudden, within few days or
may appear acutely on pre-existing chronic variety.
•The chronic variety is 10 times commoner than the acute one.
•Acute Polyhydramnios: Onset is acute usually occurs before 20 weeks of
pregnancy and presents usually with symptoms and labourstarts before 28
weeks of pregnancy.
•It may present as
Acute abdomen -abdominal pain, nausea, vomiting
Breathlessness which increases on lying down position
Palpitation
Oedemaof legs, varicosities in legs, vulva and hemorroids
•Signs:
Patient looks ill, with out features of shock
Oedemaof legs with signs of PIH
Abdomen unduly enlarged with shiny skin
Fluid thrill may be present
•Internal examination shows taking up of cervix or even dilatation with bulging
membranes
pregnancy and presents usually with symptoms and labourstarts before 28
weeks of pregnancy.
•It may present as
Acute abdomen -abdominal pain, nausea, vomiting
Breathlessness which increases on lying down position
Palpitation
Oedemaof legs, varicosities in legs, vulva and hemorroids
•Signs:
Patient looks ill, with out features of shock
Oedemaof legs with signs of PIH
Abdomen unduly enlarged with shiny skin
Fluid thrill may be present
•Internal examination shows taking up of cervix or even dilatation with bulging
membranes
•Chronic Polyhydramnios: More common than acute 10% more common
•Since accumulation of liquor is gradual and so patient may be symptomatic or
asymptomatic.
•Symptoms are mainly due to mechanical causes
Dyspnoea is more in supine position
Palpitation
Oedema
Oliguria may result from ureteral obstruction by enlarged uterus
•Pre-eclampsia 25 %( oedema, hypertension and proteinuria)
•Since accumulation of liquor is gradual and so patient may be symptomatic or
asymptomatic.
•Symptoms are mainly due to mechanical causes
Dyspnoea is more in supine position
Palpitation
Oedema
Oliguria may result from ureteral obstruction by enlarged uterus
•Pre-eclampsia 25 %( oedema, hypertension and proteinuria)
Signs GPE
•Patient may be dyspnoicat rest
•Pedal Oedema
•Evidence of PIH
Abdominal examination
Inspection
•Abdomen is markedly enlarged globular with fullness in flanks
•Skin over the abdomen is tense shiny with large striae
•Patient may be dyspnoicat rest
•Pedal Oedema
•Evidence of PIH
Abdominal examination
Inspection
•Abdomen is markedly enlarged globular with fullness in flanks
•Skin over the abdomen is tense shiny with large striae
Palpation:
•Height of uterus is more than the corresponding periods of
Amenorrhoea
•Abdominal girth is more
•Fetal parts cannot be well defined external ballotmentis more easily
elicited
•Malpresentationsare more common and presenting part is usually
high up
•Fluid thrill is present
Auscultation
•Fetal heart sounds are not heard distinctly
•Height of uterus is more than the corresponding periods of
Amenorrhoea
•Abdominal girth is more
•Fetal parts cannot be well defined external ballotmentis more easily
elicited
•Malpresentationsare more common and presenting part is usually
high up
•Fluid thrill is present
Auscultation
•Fetal heart sounds are not heard distinctly
Internal examination:
Cervix is pulled up
May be sometimes dilated and admits tip of finger through which
bag of membranes which is tense is felt.
•At times patient may present with complications like
Pre ecclampsia
PROM
Preterm labour
Placental abruption
Cord prolapse
Cervix is pulled up
May be sometimes dilated and admits tip of finger through which
bag of membranes which is tense is felt.
•At times patient may present with complications like
Pre ecclampsia
PROM
Preterm labour
Placental abruption
Cord prolapse
▪The diagnostic approach to polyhydramnios consists of
(1) physical examination of the mother with an investigation for
diabetes mellitus, diabetes insipidus, and Rh isoimmunization;
(2) sonographic confirmation of polyhydramnios and assessment of
the fetus;
(3) fetal karyotyping; and
(4) maternal serologic testing for syphilis.
(1) physical examination of the mother with an investigation for
diabetes mellitus, diabetes insipidus, and Rh isoimmunization;
(2) sonographic confirmation of polyhydramnios and assessment of
the fetus;
(3) fetal karyotyping; and
(4) maternal serologic testing for syphilis.
Sonogram of severe hydramnios at 35 weeks in a
pregnancy complicated by fetal aqueductal stenosis. This
pocket
of amnionic fluid measures more than 15 cm, and the amnionic
fluid index measured nearly 50 cm
pregnancy complicated by fetal aqueductal stenosis. This
of amnionic fluid measures more than 15 cm, and the amnionic
fluid index measured nearly 50 cm
Management:
•Routine OBH
•History suggestive of Rh iso-immunization such as still birth, fetal hydrops, jaundice
in new born requiring exchange transfusion etc.
•History suggestive of DM –Previous big baby fetal death at 35 weeks, classical
symptoms of DM like polyurea, polydypsia, polyphagia
•History of Drug intake especially in First trimester
•History of Previous fetal anomalies like Anencephaly-risk of recurrence is 2%
•Routine OBH
•History suggestive of Rh iso-immunization such as still birth, fetal hydrops, jaundice
in new born requiring exchange transfusion etc.
•History suggestive of DM –Previous big baby fetal death at 35 weeks, classical
symptoms of DM like polyurea, polydypsia, polyphagia
•History of Drug intake especially in First trimester
•History of Previous fetal anomalies like Anencephaly-risk of recurrence is 2%
•Management
•As noted previously, hydramniosetiologiesare varied, and treatment
is directed in most situations to the underlying cause.
•Occasionally, severe hydramniosmay result in early preterm laboror
the development of maternal respiratory compromise.
•In such cases, large-volume amniocentesis—termed
amnioreduction—may be needed.
•However, either an evacuated container bottle or a larger syringe is
connected to the needle via sterile intravenous tubing with a
stopcock.
•In general, approximately 1000 to 1500 mLof fluid is slowly
withdrawn during approximately 30 minutes, depending on the
severity of hydramniosand gestational age.
•As noted previously, hydramniosetiologiesare varied, and treatment
is directed in most situations to the underlying cause.
•Occasionally, severe hydramniosmay result in early preterm laboror
the development of maternal respiratory compromise.
•In such cases, large-volume amniocentesis—termed
amnioreduction—may be needed.
•However, either an evacuated container bottle or a larger syringe is
connected to the needle via sterile intravenous tubing with a
stopcock.
•In general, approximately 1000 to 1500 mLof fluid is slowly
withdrawn during approximately 30 minutes, depending on the
severity of hydramniosand gestational age.
•The goal is to restore amnionicfluid volume to upper normal range
Hydramniossevere enough to necessitate amnioreductionalmost
invariably has an underlying etiology, and subsequent
amnioreductionprocedures may be required as often as weekly or
even semiweekly.
•Importantly, amnioreductionis typically performed later in gestation
and carries additional risks of membrane rupture, preterm laboror its
exacerbation, and placental abruption.
Hydramniossevere enough to necessitate amnioreductionalmost
invariably has an underlying etiology, and subsequent
amnioreductionprocedures may be required as often as weekly or
even semiweekly.
•Importantly, amnioreductionis typically performed later in gestation
and carries additional risks of membrane rupture, preterm laboror its
exacerbation, and placental abruption.
Amnioreduction:
Indomethacin:
•2.2-3 mg/kg/day (75 mg twice daily/25 mg every 6 hours).
•It has been found to decrease amniotic fluid as it reduces fetalurine
output.
•determine the effect
•a-) maternal symptoms and uterine contractions;
•b) weekly measurement of fundalheight and abdominal girth at the
level of the umbilicus and serial ultrasound (to monitor foetalgrowth
and amniotic fluid); and
•c) prolongation of pregnancy.
•2.2-3 mg/kg/day (75 mg twice daily/25 mg every 6 hours).
•It has been found to decrease amniotic fluid as it reduces fetalurine
output.
•determine the effect
•a-) maternal symptoms and uterine contractions;
•b) weekly measurement of fundalheight and abdominal girth at the
level of the umbilicus and serial ultrasound (to monitor foetalgrowth
and amniotic fluid); and
•c) prolongation of pregnancy.
Complication:
•With chronic hydramnios, fluid accumulates gradually, and a woman
may tolerate excessive abdominal distentionwith relatively little
discomfort.
•Acute hydramnios, however, tends to develop earlier in pregnancy. It
may result in preterm laborbefore 28 weeks or in symptoms that
become so debilitating as to necessitate intervention.
•With chronic hydramnios, fluid accumulates gradually, and a woman
may tolerate excessive abdominal distentionwith relatively little
discomfort.
•Acute hydramnios, however, tends to develop earlier in pregnancy. It
may result in preterm laborbefore 28 weeks or in symptoms that
become so debilitating as to necessitate intervention.
•Symptoms may arise from pressure exerted within the overdistended
uterus and upon adjacent organs.
•When distentionis excessive, the mother may suffer dyspneaand
orthopneato such a degree that she may be able to breathe
comfortably only when upright
•Edemamay develop as a consequence of major venous system
compression by the enlarged uterus, and it tends to be most
pronounced in the lower extremities, vulva, and abdominal wall.
uterus and upon adjacent organs.
•When distentionis excessive, the mother may suffer dyspneaand
orthopneato such a degree that she may be able to breathe
comfortably only when upright
•Edemamay develop as a consequence of major venous system
compression by the enlarged uterus, and it tends to be most
pronounced in the lower extremities, vulva, and abdominal wall.
•Rarely, oliguriamay result from ureteralobstruction by the enlarged
uterus.
•Maternal complications such as these are typically associated with
severe hydramniosfrom an underlying etiology.
uterus.
•Maternal complications such as these are typically associated with
severe hydramniosfrom an underlying etiology.
•Maternal complications: associated with hydramniosinclude
placental abruption, uterine dysfunction, and postpartum
hemorrhage.
•Placental abruption is fortunately infrequent. It may result from the
rapid decompression of an overdistendeduterus that follows fetal-
membrane rupture or therapeutic amnioreduction.
•With prematurely ruptured membranes, a placental abruption
occasionally occurs days or weeks after amniorrhexis.
•Uterine dysfunction consequent to overdistentionmay lead to
postpartum atonyand, in turn, postpartum hemorrhage.
placental abruption, uterine dysfunction, and postpartum
hemorrhage.
•Placental abruption is fortunately infrequent. It may result from the
rapid decompression of an overdistendeduterus that follows fetal-
membrane rupture or therapeutic amnioreduction.
•With prematurely ruptured membranes, a placental abruption
occasionally occurs days or weeks after amniorrhexis.
•Uterine dysfunction consequent to overdistentionmay lead to
postpartum atonyand, in turn, postpartum hemorrhage.
Complication :
I. Maternal :
A) During Pregnancy :
1-Abortion (as a result of overdistensionof the uterus).
2-Preterm labour.
3-Premature rupture of membranes.
4-Cord prolapse.
5-Placental abruption.
6-Malpresentation.
7-Nonengagementof the presenting part.
8-Pressure symptoms : as dyspnea, palpitation and edema
of lower limbs.
I. Maternal :
A) During Pregnancy :
1-Abortion (as a result of overdistensionof the uterus).
2-Preterm labour.
3-Premature rupture of membranes.
4-Cord prolapse.
5-Placental abruption.
6-Malpresentation.
7-Nonengagementof the presenting part.
8-Pressure symptoms : as dyspnea, palpitation and edema
of lower limbs.
B) During Labour:
1-Premature rupture of membranes.
2-Prolapse of arm, cord or both.
3-Abruptioplacentae due to rapid escape of liquor with premature separation
of the placenta.
4-Splanchnic shock occurs if the fluid escapes rapidly, so the pressure exerted
by the uterus on the splanchnic vessels drops suddenly leading to pooling of
blood in the splanchnic area and shock.
5-Postpartum hemorrhage due to :
-Uterine atony due to overdistensionof the uterus.
-Retained placenta.
-Prolonged labour.
C) During Purperium: The uterus may take a longer time to involute
(subinvolution).
1-Premature rupture of membranes.
2-Prolapse of arm, cord or both.
3-Abruptioplacentae due to rapid escape of liquor with premature separation
of the placenta.
4-Splanchnic shock occurs if the fluid escapes rapidly, so the pressure exerted
by the uterus on the splanchnic vessels drops suddenly leading to pooling of
blood in the splanchnic area and shock.
5-Postpartum hemorrhage due to :
-Uterine atony due to overdistensionof the uterus.
-Retained placenta.
-Prolonged labour.
C) During Purperium: The uterus may take a longer time to involute
(subinvolution).
Amniotic fluid testing
Chromosome and DNA analysis
Biochemistry
Fetalinfections
Rhdisease and other alloimmunisation
Lung maturity
Chorioamnionitis
Obstetric cholestasis
Fetaltherapy-decompression
severe oligohydramnios
multifetalpregnancy reduction
throxinetherapy
Chromosome and DNA analysis
Biochemistry
Fetalinfections
Rhdisease and other alloimmunisation
Lung maturity
Chorioamnionitis
Obstetric cholestasis
Fetaltherapy-decompression
severe oligohydramnios
multifetalpregnancy reduction
throxinetherapy
AMNIOCENTESIS
•Usually performed between 16-20 weeks of gestation.
•Procedure performed using ultrasound guidance and sterile
technique.
•Typically performed by two operators.
•The main operator performs the invasive procedure while the
assistant performs the ultrasound examination and guides the
needle insertion.
•Pre procedure ultrasound examination is performed to identify
the placental location and fetal position in an attempt to avoid
both during the needle insertion.
•Usually performed between 16-20 weeks of gestation.
•Procedure performed using ultrasound guidance and sterile
technique.
•Typically performed by two operators.
•The main operator performs the invasive procedure while the
assistant performs the ultrasound examination and guides the
needle insertion.
•Pre procedure ultrasound examination is performed to identify
the placental location and fetal position in an attempt to avoid
both during the needle insertion.
•The desired area of the maternal abdomen is cleaned, sterilized
and draped with sterile drapes.
•Ultrasound probe covered by sterile sleeve an continuous
ultrasound guidance is provided during the procedure.
•Ultrasound probe held vertically and the desired target is
centered on the screen.
•Needle guide is attached to the probe laterally , which provides
a needle track ,at a 45◦angle to the horizontal plane.
and draped with sterile drapes.
•Ultrasound probe covered by sterile sleeve an continuous
ultrasound guidance is provided during the procedure.
•Ultrasound probe held vertically and the desired target is
centered on the screen.
•Needle guide is attached to the probe laterally , which provides
a needle track ,at a 45◦angle to the horizontal plane.
❖Alternative:
❖Free hand needle insertion can be done , the needle is inserted 3 cm
lateral to the probe, in the same plane and at 45◦angle.
❖The guide increases the ease of needle insertion & reduces the risks
of failed attempts and complications.
❖5 inch length 22 gauge spinal needle is used.
❖Rarely 7 inch length needle is used in obese patients.
❖Free hand needle insertion can be done , the needle is inserted 3 cm
lateral to the probe, in the same plane and at 45◦angle.
❖The guide increases the ease of needle insertion & reduces the risks
of failed attempts and complications.
❖5 inch length 22 gauge spinal needle is used.
❖Rarely 7 inch length needle is used in obese patients.
•Amniotic sac is entered and fluid is aspirated using sterile syringes.
•The first 1-2ml of the amniotic fluid may be contaminated by
maternal cells and can be discarded.
•Fluid subsequently aspirated can be sent for fetal chromosomal
analysis after tissue culture or direct fluorescent insitu hybridization
techniques.
•Amount required for chromosomal analysis : 15-20 ml.
•The first 1-2ml of the amniotic fluid may be contaminated by
maternal cells and can be discarded.
•Fluid subsequently aspirated can be sent for fetal chromosomal
analysis after tissue culture or direct fluorescent insitu hybridization
techniques.
•Amount required for chromosomal analysis : 15-20 ml.
•Pregnancy loss rate : 1 in 200
•Complications :
•Infection
•Inadvertent trauma to the fetus or placenta
•Leakage of amniotic fluid
•Miscarriage.
•Feto maternal hemorrhage,
•Isoimmunization may occur in Rh negative women and it
should be covered by prophylactic antiD in non sensitized
women.
•Complications :
•Infection
•Inadvertent trauma to the fetus or placenta
•Leakage of amniotic fluid
•Miscarriage.
•Feto maternal hemorrhage,
•Isoimmunization may occur in Rh negative women and it
should be covered by prophylactic antiD in non sensitized
women.
Early amniocentesis:
•12-14 WEEKS
•Done in order to obtain the results earlier in gestation
•Increase in risk of talipesequinovarus.
•For patients desiring earlier diagnosis , transabdominalCVS should
be preferred over early amniocentesis.
•12-14 WEEKS
•Done in order to obtain the results earlier in gestation
•Increase in risk of talipesequinovarus.
•For patients desiring earlier diagnosis , transabdominalCVS should
be preferred over early amniocentesis.
Amniotic fluid testing
•TestingamnioticfluidforAFPandAChEcanpredictopenneuraltube
defectsmoreaccuratelythanmaternalserumscreening.
•PatientwithunexplainedhighmaternalserumAFPlevelsandnormal
ultrasonographyfindingsshouldbeofferedamnioticfluidtesting.
•Anypatientwhohashadachildwithaneuraltubedefecthas3%
to5%riskforrecurrenceandalsoshouldbeofferedamnioticfluid
AFPtesting
•AnyelevationofAFPinamnioticfluidshouldleadtoAChEanalysis
•TestingamnioticfluidforAFPandAChEcanpredictopenneuraltube
defectsmoreaccuratelythanmaternalserumscreening.
•PatientwithunexplainedhighmaternalserumAFPlevelsandnormal
ultrasonographyfindingsshouldbeofferedamnioticfluidtesting.
•Anypatientwhohashadachildwithaneuraltubedefecthas3%
to5%riskforrecurrenceandalsoshouldbeofferedamnioticfluid
AFPtesting
•AnyelevationofAFPinamnioticfluidshouldleadtoAChEanalysis
Amniotic fluid testing
•Testingshouldbeperformedatorbefore16weeksgestation.
•Determinationoffetalkaryotypeisalsoreasonable.
•Testingshouldbeperformedatorbefore16weeksgestation.
•Determinationoffetalkaryotypeisalsoreasonable.
Amniocentesis role in Rhdisease and alloimmunisation
•Amniocentesis and estimation of bilirubinin the amniotic fluid by
spectrophotometryare indicated in—
•(1) Antibody titerrises more than 1: 8 to determine whether the
particular baby will be affected or not;
•(2) Previous history of severely affected baby;
•(3) Father is heterozygous to determine whether the particular baby
will be affected or not. As such, if Rhantibodies are found in the
current pregnancy, it is an essential procedure to guide the
management.
•Amniocentesis and estimation of bilirubinin the amniotic fluid by
spectrophotometryare indicated in—
•(1) Antibody titerrises more than 1: 8 to determine whether the
particular baby will be affected or not;
•(2) Previous history of severely affected baby;
•(3) Father is heterozygous to determine whether the particular baby
will be affected or not. As such, if Rhantibodies are found in the
current pregnancy, it is an essential procedure to guide the
management.
•Selection of time—
•(1) No history of previously affected baby—It is done at 30–32
weeks and a second test should be repeated after 3–4 weeks;
•(2) Positive history of previously affected baby—It should be done
atleast10 weeks prior to the date of previous stillbirth or other
hemolyticmanifestations on the baby.
•However, it is useless to perform prior to 20 weeks.
•(1) No history of previously affected baby—It is done at 30–32
weeks and a second test should be repeated after 3–4 weeks;
•(2) Positive history of previously affected baby—It should be done
atleast10 weeks prior to the date of previous stillbirth or other
hemolyticmanifestations on the baby.
•However, it is useless to perform prior to 20 weeks.
Inference:
•The optical density of the liquor containing the bilirubinpigment, is
observed at 250–700 nm wave length.
•The optical density difference at 450 nm wave length gives the
prediction of the severity of fetalhemolysis.
•In presence of bilirubin, there is a “deviation bulge” peaking at 450
nm wave length.
•The bigger the deviation bulge, the more severe is the affection of
the baby. For any given period of gestation, the height of the
spectrophotometric“deviation bulge” at ΔOD450 falls within one of
the three zones when plotted in Liley’schart.
•The optical density of the liquor containing the bilirubinpigment, is
observed at 250–700 nm wave length.
•The optical density difference at 450 nm wave length gives the
prediction of the severity of fetalhemolysis.
•In presence of bilirubin, there is a “deviation bulge” peaking at 450
nm wave length.
•The bigger the deviation bulge, the more severe is the affection of
the baby. For any given period of gestation, the height of the
spectrophotometric“deviation bulge” at ΔOD450 falls within one of
the three zones when plotted in Liley’schart.
Spectrophotometricanalysis of amniotic fluid
showing optical density difference at 450 nm wave length with
“deviation bulge” in Rhhemolyticdisease
Plotting of the “deviation bulge” in Liley’s
prediction
chart at different periods of gestation
showing optical density difference at 450 nm wave length with
“deviation bulge” in Rhhemolyticdisease
Plotting of the “deviation bulge” in Liley’s
prediction
chart at different periods of gestation
Predictions:
•Liley’szone I (low zone): The fetusis unlikely to be affected and the
pregnancy can be continued to term.
•Liley’szone II (mid zone): Repeat amniocentesis by 2 weeks →
value upward → cordocentesis→ hematocrit< 30% → intrauterine
transfusion to raise haematocrit40–45%. Preterm delivery may be
needed after 34 weeks.
•Liley’szone III (High zone): The fetusis severely affected and death
is imminent. Pregnancy > 34 weeks→ delivery.
Pregnancy <34 weeks → cordocentesis→ hematocrit< 30% →
intrauterine transfusion to raise hematocrit40–45%. Preterm
delivery may be needed after 34 weeks.
•Liley’szone I (low zone): The fetusis unlikely to be affected and the
pregnancy can be continued to term.
•Liley’szone II (mid zone): Repeat amniocentesis by 2 weeks →
value upward → cordocentesis→ hematocrit< 30% → intrauterine
transfusion to raise haematocrit40–45%. Preterm delivery may be
needed after 34 weeks.
•Liley’szone III (High zone): The fetusis severely affected and death
is imminent. Pregnancy > 34 weeks→ delivery.
Pregnancy <34 weeks → cordocentesis→ hematocrit< 30% →
intrauterine transfusion to raise hematocrit40–45%. Preterm
delivery may be needed after 34 weeks.
Advantages:
•Spectrophotometricanalysis when plotted in relation to the Liley’s
zone can predict with fair degree of accuracy, the degree of
hemolyticprocess in the fetus.
•This can give indications when to terminate the pregnancy and when
to give intrauterine fetaltransfusion.
•Assessment of fetalanemiais more accurate by fetalumbilical cord
blood sampling
•Cordocentesisalso helps to detect fetalblood type, hematocrit, DCT
and total bilirubinlevel.
•Fetalhematocritvalue <15 percent is associated with hydrops.
•Spectrophotometricanalysis when plotted in relation to the Liley’s
zone can predict with fair degree of accuracy, the degree of
hemolyticprocess in the fetus.
•This can give indications when to terminate the pregnancy and when
to give intrauterine fetaltransfusion.
•Assessment of fetalanemiais more accurate by fetalumbilical cord
blood sampling
•Cordocentesisalso helps to detect fetalblood type, hematocrit, DCT
and total bilirubinlevel.
•Fetalhematocritvalue <15 percent is associated with hydrops.
Tests for Lung Maturity
1. Lecithin/ sphingomyelin ratio
a.Method:____________________________
b.Principles: Lecithin is produced at a relatively low and constant rate until the 35
th
week of gestation
while sphingomyelin is produced at a constant rate after about 26 week’ gestation and therefore conserve
as a control on which to base the rise in lecithin. Prior to 35 week’ gestation, L/S ratio is ˂1.6 and rises
to >2.0 when lecithin production increases.
2. Amniostat-FLM
a.Method:________________________
b.Principle: the test uses antisera for phosphatidly glycerol and is affectected by specimen contamination with blood and
meconium.
1. Lecithin/ sphingomyelin ratio
a.Method:____________________________
b.Principles: Lecithin is produced at a relatively low and constant rate until the 35
th
week of gestation
while sphingomyelin is produced at a constant rate after about 26 week’ gestation and therefore conserve
as a control on which to base the rise in lecithin. Prior to 35 week’ gestation, L/S ratio is ˂1.6 and rises
to >2.0 when lecithin production increases.
2. Amniostat-FLM
a.Method:________________________
b.Principle: the test uses antisera for phosphatidly glycerol and is affectected by specimen contamination with blood and
meconium.
3. Foam stability index
a.method:_____________________________
b.Principle: a semiquatitative measure of the amount of surfactant is done by adding 0.5 mL of amniotic fluid to increasing
amounts of 95% ethanol (0.42 mL to 0.55 mL in 0.01-mL increments), shaken for 15 seconds, and allowed to sit undisturbed
for 15 minutes. If a sufficient amount of phospholipid is present, a continuous line of bubbles will be observed even in the
presence of alcohol, an anti-foaming agent.
4. Microviscosity
a.Method:______________________
b.Principle: Phospholipids decrease the microviscosity of amniotic fluid and the change is detected by determining the
surfactant to albumin ratio (mg/g) based on the polarization of a fluorescent dye that combines (internal standard,
decreased fluorescence lifetime and high polarization).
a.method:_____________________________
b.Principle: a semiquatitative measure of the amount of surfactant is done by adding 0.5 mL of amniotic fluid to increasing
amounts of 95% ethanol (0.42 mL to 0.55 mL in 0.01-mL increments), shaken for 15 seconds, and allowed to sit undisturbed
for 15 minutes. If a sufficient amount of phospholipid is present, a continuous line of bubbles will be observed even in the
presence of alcohol, an anti-foaming agent.
4. Microviscosity
a.Method:______________________
b.Principle: Phospholipids decrease the microviscosity of amniotic fluid and the change is detected by determining the
surfactant to albumin ratio (mg/g) based on the polarization of a fluorescent dye that combines (internal standard,
decreased fluorescence lifetime and high polarization).
5. Lamellar body count
a.Method:___________________________
b.Principle: Lamellar bodies (lamellated phospholipids that represent a storage from of surfactants secreted by the type
II pneumocytes of the fetal lung)range in size from 1.7 to 7.3 fL, and therefore can be counted using the platelet
channel of hematology analyzers.
6. Optical density at 650 nm
a.Method:_________________________
b.Principle : the increase in OD of the amniotic fluid caused by the presence of lamella bodies in determined by
centrifuging the specimen at 2000 g for 10 min and reading the absorbance at 650 nm.
a.Method:___________________________
b.Principle: Lamellar bodies (lamellated phospholipids that represent a storage from of surfactants secreted by the type
II pneumocytes of the fetal lung)range in size from 1.7 to 7.3 fL, and therefore can be counted using the platelet
channel of hematology analyzers.
6. Optical density at 650 nm
a.Method:_________________________
b.Principle : the increase in OD of the amniotic fluid caused by the presence of lamella bodies in determined by
centrifuging the specimen at 2000 g for 10 min and reading the absorbance at 650 nm.
Table 24. Tests for fetal lung maturity
Normal values Significance
L/Sratio ≥2.0 FLM
Amniostat-FLM Positive FLM/phosphotidylglycerol
Foams Stability index ≥47 FLM
Microviscosity ≥55 mg/g FLM
Lamellarbody count ≥32,00/ mL FLM
ODat 650 nm ≥0.150 FLM
Bilirubinscan A 450 less .025HDN
Alpha Fetoprotein Lessthan 2.0
MoM
Neural tube disorder
Normal values Significance
L/Sratio ≥2.0 FLM
Amniostat-FLM Positive FLM/phosphotidylglycerol
Foams Stability index ≥47 FLM
Microviscosity ≥55 mg/g FLM
Lamellarbody count ≥32,00/ mL FLM
ODat 650 nm ≥0.150 FLM
Bilirubinscan A 450 less .025HDN
Alpha Fetoprotein Lessthan 2.0
MoM
Neural tube disorder
Test for Fetal Distress
1. Bilirubin assay
a.Method: _____________________
b.Principle: the optical density of amniotic fluid is normally highest at 365 nm and decreases linearly to 550 nm
except when bilirubin is present where a rise in OD is seen at 450 nm. The ᴧᴬ450 is then plotted on a liley graph
to determine the severity of HDN and the need for interventions.
2. Alpha fetoprotein
a.Method:_________________
b.Principle: The Test is based on the measurement of the neural tube defects using an automated
immunoassay method: results are reported in terms of multiples of the median with a value >2 MoM
considered abnormal
1. Bilirubin assay
a.Method: _____________________
b.Principle: the optical density of amniotic fluid is normally highest at 365 nm and decreases linearly to 550 nm
except when bilirubin is present where a rise in OD is seen at 450 nm. The ᴧᴬ450 is then plotted on a liley graph
to determine the severity of HDN and the need for interventions.
2. Alpha fetoprotein
a.Method:_________________
b.Principle: The Test is based on the measurement of the neural tube defects using an automated
immunoassay method: results are reported in terms of multiples of the median with a value >2 MoM
considered abnormal
3. Acetylcholinesterase
a.Method: ____________________
b.Principle: Ache is an enzyme derived primarily from the neural tissue and is normally absent in amniotic
fluid. Its presence in amniotic fluid in conjunction with elevated AFP values is highly diagnostic of NTDs.
a.Method: ____________________
b.Principle: Ache is an enzyme derived primarily from the neural tissue and is normally absent in amniotic
fluid. Its presence in amniotic fluid in conjunction with elevated AFP values is highly diagnostic of NTDs.
Other Tests
1. Differentiation of amniotic fluid from maternal urine
•Creatinine is ˂3.5 mg/ dL and urea is ˂30 mg/dL in amniotic
fluid, whereas high as 10 mg/ dL creatinine and 300 mg/dL
urea may be found in urine
2. Determination of fetal age
•AF creatinine level ranges from 1.5 to 2.0 mg/ dL prior to 36
weeks’ gestation and rises above 2.0 mg/dL thereafter,
providing a means of determining fetal age as >36 weeks
3. Kleihauer-Betke test
•used to determine the source of the blood (maternal or
fetal) in a bloody specimen for further case management.
1. Differentiation of amniotic fluid from maternal urine
•Creatinine is ˂3.5 mg/ dL and urea is ˂30 mg/dL in amniotic
fluid, whereas high as 10 mg/ dL creatinine and 300 mg/dL
urea may be found in urine
2. Determination of fetal age
•AF creatinine level ranges from 1.5 to 2.0 mg/ dL prior to 36
weeks’ gestation and rises above 2.0 mg/dL thereafter,
providing a means of determining fetal age as >36 weeks
3. Kleihauer-Betke test
•used to determine the source of the blood (maternal or
fetal) in a bloody specimen for further case management.
THANK YOU…!!!
THANK YOU
•ARM
•AMNIOTIC FLUID EMBOLISM
•AMNIOTIC FLUID EMBOLISM
DIAGNOSTIC USES
•Amniocentesis:
•Transabdominal withdrawal o f amnionic fluid remains the most
common procedure used to diagnose fetal aneuploidy and other
genetic conditions.
•It is generally performed between 15 and 20 weeks’ gestation but
may be performed later as well.
•The indication is usually to assess fetal karyotype, although use of
FISH and array-based comparative genomic hybridization studies
have increased considerably.
•Amniocentesis:
•Transabdominal withdrawal o f amnionic fluid remains the most
common procedure used to diagnose fetal aneuploidy and other
genetic conditions.
•It is generally performed between 15 and 20 weeks’ gestation but
may be performed later as well.
•The indication is usually to assess fetal karyotype, although use of
FISH and array-based comparative genomic hybridization studies
have increased considerably.
•Because the amniocytes must be cultured before fetal karyotype can
be assessed, the time needed for karyotyping is 7 to 10 days.
•Outside the context of prenatal genetic analysis, amnionic fluid
occasionally may be removed in large amounts therapeutically to
relieve symptomatic hydramnios .
be assessed, the time needed for karyotyping is 7 to 10 days.
•Outside the context of prenatal genetic analysis, amnionic fluid
occasionally may be removed in large amounts therapeutically to
relieve symptomatic hydramnios .
•Technique: Amniocentesis is performed using aseptic technique,
under direct sonographic guidance, using a 20-to 22-gauge spinal
needle.
•A standard spinal needle is approximately 9 cm long, and depending
on patient habitus, a longer needle may be required. The needle is
directed into a clear pocket of amnionic fluid, while avoiding the fetus
and umbilical cord and ideally without traversing the placenta.
•Efforts are made to puncture the chorioamnion rather than to “tent”
it away from the underlying uterine wall. (Mujezinovic, 2011).
under direct sonographic guidance, using a 20-to 22-gauge spinal
needle.
•A standard spinal needle is approximately 9 cm long, and depending
on patient habitus, a longer needle may be required. The needle is
directed into a clear pocket of amnionic fluid, while avoiding the fetus
and umbilical cord and ideally without traversing the placenta.
•Efforts are made to puncture the chorioamnion rather than to “tent”
it away from the underlying uterine wall. (Mujezinovic, 2011).
AF and Respiratory distress syndrome (RDS)
AF and Respiratory distress syndrome (RDS)
•Respiratorydistresssyndrome(RDS)wasassociatedwitha
significantmortalityrateapproachingapproximately30%.
•Inthe1950s,itwasdiscoveredthattheresistanceof
pulmonaryalveolitocollapseduringexpirationwasmainly
causedbythepresenceofasurfacetension-lowering
materialliningthealveolus(surfactant).
•Asthelungsdevelop,significantquantitiesofsurfactantare
washedoutofthefetallungandaccumulateintheamniotic
fluid.
•Respiratorydistresssyndrome(RDS)wasassociatedwitha
significantmortalityrateapproachingapproximately30%.
•Inthe1950s,itwasdiscoveredthattheresistanceof
pulmonaryalveolitocollapseduringexpirationwasmainly
causedbythepresenceofasurfacetension-lowering
materialliningthealveolus(surfactant).
•Asthelungsdevelop,significantquantitiesofsurfactantare
washedoutofthefetallungandaccumulateintheamniotic
fluid.
AF and Respiratory distress syndrome (RDS)
•Alloftheavailablebiochemicaltestsforfetallungmaturityrelyon
theamnioticfluidcontentofsurfactant.
•Adultmaturesurfactantisapproximately80%phospholipids,about
10%protein,andabout10%neutrallipids(primarilycholesterol).
•Themajorspeciesofphospholipidinsurfactantis
phosphatidylcholine(alsoreferredtoaslecithin),whichaccounts
for80%ofthetotalphospholipid.
•Alloftheavailablebiochemicaltestsforfetallungmaturityrelyon
theamnioticfluidcontentofsurfactant.
•Adultmaturesurfactantisapproximately80%phospholipids,about
10%protein,andabout10%neutrallipids(primarilycholesterol).
•Themajorspeciesofphospholipidinsurfactantis
phosphatidylcholine(alsoreferredtoaslecithin),whichaccounts
for80%ofthetotalphospholipid.
L/S ratio test
•TheL/Sratiotestremainsoneofthemostcommonlyusedtests,
andoneofthestandardizedtestsagainstwhichallothertestsare
compared.
•WithaL/Sratioof1.5-1.9,approximately50%ofinfantswill
developRDS.Belowaratioof1.5,theriskofsubsequentRDS
increasesto73%.
•OneofthemajordisadvantagesoftheL/Sratioistheinabilityto
usethistestinthesettingofcontaminatedamnioticfluid.Both
bloodandmeconiumstainingofamnioticfluidhavebeenfoundto
interferewithL/Sratiodeterminations.
•TheL/Sratiotestremainsoneofthemostcommonlyusedtests,
andoneofthestandardizedtestsagainstwhichallothertestsare
compared.
•WithaL/Sratioof1.5-1.9,approximately50%ofinfantswill
developRDS.Belowaratioof1.5,theriskofsubsequentRDS
increasesto73%.
•OneofthemajordisadvantagesoftheL/Sratioistheinabilityto
usethistestinthesettingofcontaminatedamnioticfluid.Both
bloodandmeconiumstainingofamnioticfluidhavebeenfoundto
interferewithL/Sratiodeterminations.
PG determinations:
▪Itisfoundthatthefalse-positiverateforPGdeterminationwas
1.8%.Thisrateissignificantlylowerthanthefalse-positiverate
theyfoundfortheL/Sratio(5%).
▪PGperformsmuchbetterthantheL/Sratioinpredictingbabies
whowilldevelopRDS.Finally,PGdeterminationsaccuratelypredict
pulmonarymaturityandgiveabetterindicationofpulmonary
immaturitythandoestheL/Sratio.
▪Itisfoundthatthefalse-positiverateforPGdeterminationwas
1.8%.Thisrateissignificantlylowerthanthefalse-positiverate
theyfoundfortheL/Sratio(5%).
▪PGperformsmuchbetterthantheL/Sratioinpredictingbabies
whowilldevelopRDS.Finally,PGdeterminationsaccuratelypredict
pulmonarymaturityandgiveabetterindicationofpulmonary
immaturitythandoestheL/Sratio.
Saturated Phosphatidylcholine
•SaturatedPhosphatidylcholinehasbeenfoundtopredictpulmonary
maturity
•Respiratorydistresssyndromewascorrectlypredicted55.5%ofthe
timebyL/Sratioand82%ofthetimebySPC.
•Pulmonaryimmaturity=anSPC<500μg/dl
•Inaddition,theSPCwasfoundtobevalidinthepresenceofblood
andmeconium,whereastheL/Sratiowasnot.
•SaturatedPhosphatidylcholinehasbeenfoundtopredictpulmonary
maturity
•Respiratorydistresssyndromewascorrectlypredicted55.5%ofthe
timebyL/Sratioand82%ofthetimebySPC.
•Pulmonaryimmaturity=anSPC<500μg/dl
•Inaddition,theSPCwasfoundtobevalidinthepresenceofblood
andmeconium,whereastheL/Sratiowasnot.
Shake test
▪Thistestusetheprinciplethatwhenethanolisaddedtoamniotic
fluid,thenonsurfactantfoamcausingsubstancesinamnioticfluid
areremoved.
▪Anystablefoamlayerthatpersistsaftershakingisduetothe
presenceofsurfactantinacriticalconcentration.
▪Whenserialdilutionsofethanolareused,thesurfactantcanbe
quantified.
▪ItisfoundthattheshaketestwascomparabletotheL/Sratioand
hadahighpredictivevalueforRDSwhenappliedto
uncontaminatedamnioticfluid.
▪Thistestusetheprinciplethatwhenethanolisaddedtoamniotic
fluid,thenonsurfactantfoamcausingsubstancesinamnioticfluid
areremoved.
▪Anystablefoamlayerthatpersistsaftershakingisduetothe
presenceofsurfactantinacriticalconcentration.
▪Whenserialdilutionsofethanolareused,thesurfactantcanbe
quantified.
▪ItisfoundthattheshaketestwascomparabletotheL/Sratioand
hadahighpredictivevalueforRDSwhenappliedto
uncontaminatedamnioticfluid.
Tap Test
•Thetaptestexaminestheabilityofsurfactantwithinamnioticfluid
tobreakdownbubbleswithinanetherlayer.
•Thetestisperformedon1mlofamnioticfluidmixedwithadropof
6Nhydrochloricacidand1.5mlofdiethylether.
•Thetubeistapped4timesandexaminedforthepresenceofbubbles
withintheetherlayer.
•Inmaturesamples,thebubblesquicklybreakdown,whereasin
immatureamnioticfluidspecimensmorethan5bubblespersistin
theetherlayer.
•Thisrapidtestwascomparablewiththephospholipidprofile.
•Thetaptestexaminestheabilityofsurfactantwithinamnioticfluid
tobreakdownbubbleswithinanetherlayer.
•Thetestisperformedon1mlofamnioticfluidmixedwithadropof
6Nhydrochloricacidand1.5mlofdiethylether.
•Thetubeistapped4timesandexaminedforthepresenceofbubbles
withintheetherlayer.
•Inmaturesamples,thebubblesquicklybreakdown,whereasin
immatureamnioticfluidspecimensmorethan5bubblespersistin
theetherlayer.
•Thisrapidtestwascomparablewiththephospholipidprofile.
Visual Inspection
•Thebasisiswhetherornotnewspapercouldbereadthroughthe
amnioticfluidsample,thatis,wasthefluidtooturbidtoreadtext
through.
•Withclearfluid(readablenewsprint)thesensitivityofanimmature
resultis98%.
•Thebasisiswhetherornotnewspapercouldbereadthroughthe
amnioticfluidsample,thatis,wasthefluidtooturbidtoreadtext
through.
•Withclearfluid(readablenewsprint)thesensitivityofanimmature
resultis98%.
Optical Density at 650 nm
•WithaOD650valueof0.15orgreater,theL/Sratiowasalways
greaterthan2.0
•WhentheOD650waslessthan0.15,only6%ofL/Sratioswere
greaterthan2
•WithaOD650valueof0.15orgreater,theL/Sratiowasalways
greaterthan2.0
•WhentheOD650waslessthan0.15,only6%ofL/Sratioswere
greaterthan2
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