Labour, Stages and its Physiology in obg

About obg unit 2

1. LABOUR, STAGES AND ITS
PHYSIOLOGY

2. INTRODUCTION
•Labororparturitionorchildbirthisthephysiologicprocessbywhich
regularlyoccurringuterinecontractionsresultsinprogressiveeffacement
anddilatationofthecervix.Thesecervicalchangespermitpassageofthe
fetus&otherproductsofconceptionfromtheuterusthroughthebirth
canal,resultingindelivery.
•Pretermorprematurelabor–happensbefore37completedweeks
•Postterm–happensafter42weeks
•Parturient–womeninlabor/birthprocess
•Eutocia–Normallabor
•Dystocia–abnormallabor(malpresentation,malpositionsetc)

3. CONTENTS
•Definitions
•Normal and abnormal labour
•Causes of onset of labour
•False labour pain and true labour pain
•Stages of labour
•Physiology of first stage of labour
•Physiology of second stage of labour
•Mechanism of normal labour
•Physiology of third stage of labour

4. DEFINITION
•Seriesofeventsthattakesplaceinthegenitalorganinanefforttoexpelthe
viableproductsofconceptionoutofthewombthroughthevaginaintothe
outerworldiscalledlabour.
•Deliveryistheexpulsionorextractionofviablefetusoutofthewomb
•Normallaborisdefinedasspontaneousinonset,remainslowriskthrough
outlabor&delivery,infantisbornspontaneouslyinvertexpositionbetween
37-41completedweeksofgestation.Bothmother&infantareingood
conditionafterbirth
-WHO
Deliveryisthespontaneousexpulsionoraidedextractionofaviablefetus
fromtheuterusvaginally(normaldelivery)orthroughabdominalroute
(Caesareandelivery)

5. NORMAL LABOUR
(EUTOCIA)
Labour is called normal if it fulfillsthe following criteria:
•Spontaneous in onset and at term.
•With vertex presentation
•Without undue prolongation
•Natural termination with minimal aids
•Without having any complications affecting the health of
mother and/or baby.

6. ABNORMAL LABOUR
(DYSTOCIA)
•Anydeviationfromthedefinitionofnormal
labouriscalledabnormallabour.

7. DEFINITION
•Premature Labour
–Labour occurring before the commencement of the 37
th
week of gestation.
•Prolonged Labour
–Labour lasting in excess of:
•24 hours in a primigravida
•16 hours in a multigravida

8. DATE OF ONSET OF LABOUR
•TheonsetofLaborisdefinedasthetimeofonsetof
regular,painfuluterinecontractions,whichproduce
progressiveeffacementanddilatationofthecervix.
•CalculationfromNaegele‘sformulaisonlyarough
guide.
•Basedontheformula,labourstartsapprox.
–ontheexpecteddatein4%,
–oneweekoneithersidein50%,
–2weeksearlierand1weeklaterin80%,
–at42weeksin10%andat43weeksplusin4%.

9. ESSENTIAL FACTORS OF LABOR
The factors affecting Labour (5P’s)
•The power (uterine activity in labour)-contraction (frequency,
duration, strength) -Voluntary bearing down effort
•The passages (birth canal)and the pelvis –fetopelvic
diameter, cervical dilatation
•The passenger (fetus) –presentation of fetus and its position
and size of fetus
•Position: maternal postures & physical positions
•Psyche: the response of the mother –emotional factor

10. CAUSES OF ONSET OF
LABOUR

11. 1. HORMONAL FACTORS

12. OESTROGEN
•Increase the release of oxytocin from maternal pituitary.
•Promotes the synthesis of receptors for oxytocin in the
myometrium and decidua.
•Increases the excitability of the myometrial cell membranes.-
last trimester

13. PROGESTERONE
•Increasedfetalproductionofdehydroepiandrosterone
sulphate(DHEA-S)andcortisolinhibitstheconversionoffetal
pregnenolonetoprogesterone.Progesteronelevelstherefore
fallbeforelabour.
•Itisthealterationintheoestrogen:progesteroneratiorather
thanthefallintheabsoluteconcentrationofprogesterone
whichislinkedwiththeprostaglandinsynthesis.

14. PROSTAGLANDINS
•Prostaglandins are the important factor which initiate and
maintain labour.
•The major sites of synthesis of prostaglandins are ---amnion,
chorion, decidual cells and myometrium.
•Synthesis is triggered by –rise in oestrogen level,
glucocorticoids, mechanical stretching in the late pregnancy,
increase in cytokines, infection, vaginal examination,
separation or rupture of membranes

15. OXYTOCIN
•Oxytocin receptors are increased in the uterus with the onset
of labour.
•Oxytocin promotes the release of prostaglandins from the
decidua.
•Oxytocin synthesis is increased in the decidua and in the
placenta.
•Vaginal examination and amniotomy cause rise in maternal
plasma oxytocin level (Ferguson reflex).
•Presence of this hormone causes the initiation of contraction
of the smooth muscles of the body & the labor pain starts

16. NEUROLOGICAL FACTOR
•Both α and β adrenergic receptors are present in the
myometrium; oestrogen causing the α receptors and
progesterone the β receptoors to function predominantly.
•The contractile response is initiated through the α receptors
of the post ganglionic nerve fibres in and around the cervix
and the lower part of the uterus.

17. FETAL CORTISOL THEORY
•Increasedcortisolproductionfromthefetaladrenalgland
beforelabormayinfluencetheonsetoflaborbyincreasing
Estrogenproductionfromtheplacenta.

18. II. MECHANICAL FACTORS

19. UTERINE DISTENSION THEORY
•When the uterus is distended to a certain limit, it starts
contraction to evacuate its contents.
•Stretch of the lower uterine segment
•It is dine by the presenting part near term.

21. PREMONITORY STAGE -PRELABOR STAGE
Lightening
Shelfing
Vaginal secretions increase in amount
Loss of weight –excretion of body water
Sciatic nerve pressure
Cervical ripening
Appearance of false labor pain
Show
Dilatation of internal os
Greater frequency of urination
Spurt of energy
Occasional rupture of membranes

22. LIGHTENING

23. SHELFING
•Itisfallingforwardsoftheuterinefundusmakingthe
upperabdomenlookslikeashelfduringstanding
position.

24. CERVICAL RIPENING

26. FALSE LABOUR PAIN
•Features
1.Dullinnature
2.Confinedtothelowerabdomenandgroin.
3.Continuousandunrelatedwithhardeningoftheuterus
4.Withoutanyeffectondilatationofthecervix.
5.Usuallyrelievedbymedications.

27. TRUE LABOUR PAIN
Features of true labour pain:
•Painful uterine contractions (labour pain) at regular intervals
•Contraction with increasing frequency, intensity and duration
•Show
•Progressive effacement and dilatation of the cervix
•Formation of the ―bag of waters.
•Not relieved by enema or sedatives

28. TRUE VS. FALSE LABOR
True False
Contraction
Regular, become closer&
stronger
Irregular
Timing Last 30-60 sec May last 1-2 min
Contraction position Lower abdomen & back Upper abdomen
Position
Get stronger with changing
position
Go away with changing
position,walking, hot bath
Cervix Dilation & effacement No changes
Fetus Dropsinto pelvis No significant changes

29. LABOR PAIN
•Throughoutpregnancy,painlessBraxtonhick
contractionswithsimultaneoushardeningofthe
uterusoccur.

30. SHOW

31. DILATATION OF INTERNAL OS

33. PRE LABOUR (PREMONITORY
STAGE) BEGINS:
•Primigravida: 2 or 3 weeks before the onset of true labour.
•Multigravida: few days prior.

34. STAGES OF LABOUR
First stage of labour
Second stage of labour
Third stage of labour
Fourth stage of labour

35. FIRST STAGE OF LABOR –
CERVICAL STAGE OF LABOR
•It begins with onset of regular uterine contractions & ends with full dilatation of the
cervix.
•Its average duration is 12 hours in primi & 6hours in multi
•It has latent, active & transition

37. SECOND STAGE OF LABOUR
•Starts from full dilatation of cervix to
expulsion of the fetus from the birth
canal.
•It has two phases
–Propulsive phase –starts from full
dilatation to descent of presenting
part to pelvic floor
–Expulsive phase –distinguished
by maternal bearing down efforts &
ends with the delivery.
The average duration is 2hours in
primi gravida and 30 min in multi

38. THIRD STAGE OF LABOUR
•Thethirdstagebeginsafterthe
expulsionoffetusandendswith
expulsionofplacentaandmembranes;
•Averagedurationisabout15minin
bothprimi&multi

39. FOURTH STAGE OF LABOUR
•Itisthestageofobservationforatleastone
hourafterexpulsionoftheafterbirth
•Beginswithdeliveryofplacentaand
extendstothefirst1-4hourspostpartum.
•Thematernalvitals,uterineretraction&
vaginalbleedingaremonitored,babyis
examinedduringthisperiod.

40. PHYSIOLOGY OF FIRST STAGE OF
LABOUR-
UTERINE ACTION
Fundal dominance:
•Each uterine contraction starts in the fundus near
one of the cornuaand spreads across and
downwards.
•The contraction lasts longest in the fundus where
it is also most intense, but the peak is reached
simultaneously over the whole uterus and the
contraction fades from all parts together.

41. POLARITY
•Polarityisthetermusedtodescribetheneuromuscularharmonythat
prevailsbetweenthetwopolesorsegmentsoftheuterusthroughout
labour.Duringeachuterinecontraction,thesetwopolesact
harmoniously.
•Theupperpolecontractsstronglyandretractstoexpelthefetus;the
lowerpolecontractsslightlyanddilatestoallowexpulsiontotakeplace.
Ifpolarityisdisorganizedthentheprogressoflabourisinhibited.

42. CONTRACTION AND RETRACTION

43. CHARACTERISTICS OF UTERINE
CONTRACTIONS
•Frequency:contractionsoccursintermittentlythroughout
labor,theybeginat20-30mapart&becomeclosertogether
until2-3min
•Regularity–contractionsoccurmoreregularlyaslabor
becomesmoreestablished
•Duration–contractionmaylastfrom30sectobetween60-90
secnearfulldilatationofthecervix
•Intensity–thestrengthofthecontractionincreasesaslabor
progresses,fromweakcontractionsnotedearlyinlabor,
strongexpulsivecontraction.

44. FORMATION OF UPPER AND
LOWER UTERINE SEGMENTS
•Theupperuterinesegment,havingbeenformedfromthe
bodyofthefundus,ismainlyconcernedwithcontractionand
retraction;itisthickandmuscular.
•Theloweruterinesegmentisformedoftheisthmusandthe
cervix,andisabout8-10cminlength.Thelowersegmentis
preparedfordistentionanddilatation.
•Themusclecontentreducesfromthefundustothecervix,
whereitisthinner.

45. FORMATION OF UPPER AND
LOWER UTERINE SEGMENTS
CONT…
•When the labour begins, the retracted longitudinal fibres in the upper
segment pull on the lower segment causing it to stretch; this is aided by
the descending presenting part.

47. THE RETRACTION RING
•Theridgeformsbetweentheupper
andloweruterinesegments;thisis
knownastheretractionring.
•Thephysiologicalringgradually
risesastheupperuterinesegment
contractsandretractsandthelower
uterinesegmentthinsoutto
accommodatethedescendingfetus.
Oncethecervixisfullydilatedand
thefetuscanleavetheuterus,the
retractionringrisesnofurther.

48. CERVICAL EFFACEMENT
•Effacement refers to the inclusion of the cervical canal into
the lower uterine segment.
•It takes place from above downward; that is, the muscle fibres
surrounding the internal os are drawn upwards by the
retracted upper segment and the cervix merges into the lower
uterine segment.
•The cervical canal widens at the level of the internal os,
where the condition of the external os remains unchanged.

49. CERVICAL EFFACEMENT
CONT…

50. CERVICAL DILATATION
•Dilatation of cervix is the process of enlargement of the os uteri from a
tightly closed aperture to an opening large enough to permit the
passage of the fetal head. Dilatation is measured in centimeters and full
dilatation at term equates to about 10 cm.

51. CERVICAL DILATATION

53. SHOW
•As a result of the dilatation of the cervix, the operculum,
which formed the cervical plug during pregnancy, is lost. The
woman may see a blood stained mucoid discharge a few
hours before, or within a few hours after, labour starts.
•The blood comes from the ruptured capillaries in the parietal
decidua where the chorion has become detached from the
dilating cervix.

54. FORMATION OF FORE WATER
•Astheloweruterinesegmentformsandstretches,the
chorionbecomesdetachedfromitandtheincreased
intrauterinepressurecausesitsloosenedpartofthesacof
fluidtobulgedownwardsintotheinternalos,tothedepthof
6-12mm.
•Thewellflexesheadfitssnuglyintothecervixandcutsoffthe
fluidinfrontoftheheadfromthatwhichsurroundsthebody.
•Theformerisknownas‗forewaters‘andthelatterthe
‗hindwaters‘.

55. FORMATION OF FORE WATER

56. GENERAL FLUID PRESSURE
•Whilethemembranesremain
intact,thepressureoftheuterine
contractionsisexertedonthe
fluidand,asfluidisnot
compressible,thepressureis
equalizedthroughouttheuterus
andthefetalbody;itisknownas
generalfluidpressure‘.

57. RUPTURE OF MEMBRANE
•Theoptimalphysiologicaltimefor
themembranes torupture
spontaneouslyisattheendofthe
firststageoflabourafterthecervix
becomesfullydilatedandno
longersupportsthebagof
forewaters.

58. FETALAXIS PRESSURE
•Duringeachcontractionthe
uterusrisesforwardandthe
forceofthefundalcontractionis
transmittedtotheupperpoleof
thefetusdownthelongaxisof
thefetusandappliedbythe
presentingparttothecervix.
Thisisknownasfetalaxis
pressure.

59. PHYSIOLOGY OF SECOND
STAGE OF LABOUR

60. INTRODUCTION TO2
ND
STAGEOFLABOR
•The2
nd
stagebeginstocompletedilataionofcervix(10cm)&
endswiththeexpulsionofthefetus.Thisstageisconcerned
withthedescentanddeliveryofthefetusthroughthebirth
canal–Expulsion
•Theexpulsiveforceofuterinecontractionsisaddedby
voluntarycontractionoftheabdominalmusclescalled
‘BearingdownEfforts’.
•TheforceatworkinnthisstageareUterineContractions,
whichoccurevery2-3mins&lasts50-60sec.

61. PHASES OF 2
ND
STAGE
Latent,descent&transitionarecharacterisedbymaternal&
verbalbehaviours,uterineactivity,theurgetobeardown&
fetaldescent.
•Thelatentphase
Thisisaperiodofrest&relativecalm.Theurgetobeardownisnot
wellestablished.
•TheDescentphase
Characterizedbystrongurgetobeardownasthenervereflexis
activatedwhenthepresentingpartpressesonthevagina&thereis
releaseofoxytocinfromtheposteriorpituitarygland,whichpromotes
strongerexpulsiveuterinecontractions
•Thetransitionphase
Thepresentingpartisontheperineum&bearingdowneffortsare
mosteffectiveforpromotingbirth.

62. SIGNS OF 2
ND
STAGE OF LABOR
•ImminentSigns
–Increasedbloodyshow
–Desiretobeardownorhavebowelmovement(resultofdescentof
presentingpart)
–Bulgingoftheperineum
–Dilatationoftheanalorifice
•ImpendingSigns
–Nausea&retching
–Irritability&uncooperativeness
–c/oseverediscomfort

63. EVENTS IN THE 2
ND
STAGE
OF LABOR

64. UTERINE ACTION
•Contractionsbecomestrongerandlongerbutmaybeless
frequent,allowingbothmotherandfetusregularrecovery
periods.
•Themembraneoftenrupturespontaneouslytowardstheend
ofthefirststageorduringtransitiontothesecondstage.
•Theconsequentdrainageofliquorallowsthehard,round
fetalheadtobedirectlyappliedtothevaginaltissues.This
pressureaidsdistension.
•Fetalaxispressureincreasesflexionofthehead,which
resultsinsmallerpresentingdiameters,morerapidprogress
andlesstraumatobothmotherandfetus

65. UTERINE ACTION CONTD…
•Thecontractionbecomesexpulsiveasthefetusdescends
furtherintothevagina.
•Pressurefromthepresentingpartstimulatesnervereceptors
inthepelvicfloor-thisistermedthe‘Fergusonreflex’andthe
womanexperiencestheneedtopush.
•Themother‘sresponseistoemployhersecondarypowersof
expulsionbycontractingherabdominalmusclesand
diaphragm.

66. SOFT TISSUE DISPLACEMENT
•As the hard fetal head descends, the soft tissues of the pelvis
becomes displaced.
–Anteriorly-Bladder
–Posteriorly-Rectum
–The levator ani muscles
–Perineal body

67. SOFT TISSUE DISPLACEMENT CONTD…
•Thefetalheadbecomesvisibleatthevulva,advancingeach
contractionandrecedingbetweencontractionsuntilcrowning
takesplace.
•Theheadisthenborn.
•Theshouldersandbodyfollowwithnextcontraction,
accompaniedbygushofamnioticfluidandsometimesof
blood.
•Thesecondstageculminatesinthebirthofthebaby.

68. MATERNAL PHYSIOLOGICAL CHANGES IN
2
ND
STAGE OF LABOR
BP
•Rise by 15-20mmHg with contractions in 2
nd
stage
Metabolism
•Maternal pushing efforts adds further skeletal muscle activity that contributes to the
increase in metabolism
Pulse rate
•Increases during each pushing effort
Temperture
•Highest elevation is at the time of delivery, an increase of 0.5 to 16c is considered
normal
GI changes
•There is reduction in gastric motility & absorption continues through 2
nd
stage
Renal & hematologic changes
•There is increased filtration & reabsorption bcozof increased co2, decrease renal
vascular resistance

69. MECHANISM OF NORMAL
LABOUR

70. LANDMARKS OF PELVIS

71. DIAMETER OF PELVIS

72. FETALSKULL

73. LIE
•It refers to the relationship of the long axis of the fetus to the long axis of
the centralized uterus or maternal spine.

74. PRESENTATION

75. PRESENTING PART
•Isdefinedasthepartofthe
presentationwhichoverliesthe
internalosandisfeltbythe
examiningfingerthroughthe
cervicalopening.

76. ATTITUDE
•The relation of the different parts of the fetus to one another is
called attitude of the fetus. The universal attitude is that of
flexion.

77. DENOMINATOR
•It is an arbitrary bony fixed point on the presenting part which
comes in relation with the various quadrants of the maternal
pelvis. The following are denominators of the different
presentations-occiput in vertex, mentum in face, frontal
eminence in brow, sacrum in breech and acromion in
shoulder

78. POSITION

79. MECHANISM OF LABOUR
•Asthefetusdescends,softtissueandbony
structuresexertpressureswhichleadto
descentthroughthebirthcanalbyaseriesof
movements.Collectively,thesemovementsare
calledthemechanismoflabour.

80. DEFINITION
•Theseriesofmovementsthatoccuronthe
headintheprocessifadaptation,duringits
journeythroughthepelvis

81. PRINCIPLES COMMON TO ALL
MECHANISM
•Descenttakesplace
•Whicheverpartleadsandfirstmeetstheresistanceofthe
pelvicfloorwillrotateforwardsuntilitcomesunderthe
symphysispubis.
•Whateveremergesfromthepelviswillpivotaroundthepubic
bone.

82. SIX CONSIDERATIONS FOR
NORMAL LABOUR
•Thelieislongitudinal
•Thepresentationiscephalic
•Thepositionisrightorleftoccipitoanterior
•Theattitudeisoneofthegoodflexion
•Thedenominatoristheocciput
•Thepresentingpartistheposteriorpartoftheanterior
parietalbone.

83. CARDINAL MOVEMENT
•Engagement
•Descent
•Flexion
•Internal rotation of the head
•Extension of the head
•External Rotation/Restitution
•Internal rotation of the shoulders
•Lateral flexion

84. ENGAGEMENT
•Themechanismbywhichthe
biparietaldiameter—thegreatest
transversediameterinanocciput
presentation—passesthroughthe
pelvicinletisdesignated
engagement.

86. DESCENT
•Thismovementisthefirstrequisitefor
birthofthenewborn.
•Differentinnulliparousandmultigravida
women.
•Throughoutthefirststageoflabourthe
contractionandretractionoftheuterine
musclesallowlessroomintheuterus,
exertingpressureonthefetusto
descend.
•Followingruptureoftheforewatersand
theexertionofmaternaleffort,progress
speedup.

87. FACTORS FACILITATING
DESCENT
•Uterine contraction & retraction
•Pressure of amniotic fluid
•Bearing down efforts
•Extension & straightening of fetal body

88. FLEXION
•Assoonasthedescendingheadmeets
resistance,whetherfromthecervix,
wallsofthepelvis,orpelvicfloor,then
flexionoftheheadnormallyresults.
•Suboccipitobregmaticdiameter(9.5cm)
issubstitutedforthelonger
occipitofrontaldiameter(10cm).The
occiputbecomestheleadingpart.

89. INTERNAL ROTATION OF THE HEAD
•Duringcontraction,theleadingpartis
pusheddownwardsontothepelvicfloor.The
resistanceofthismusculardiaphragmbrings
aboutrotation.
•Occiputgraduallymovestowardthe
symphysispubisanteriorly.
•Whicheverpartofthefetusmeetsthelateral
halfofthisslopewillbedirectedforwards
andtowardsthecenterinawellflexed
vertexpresentationtheocciputleads,and
rotatesanteriorlythrough1/8thofacircle
whenitmeetsthepelvicfloor.Thiscausesa
slighttwistintheneckastheheadisno
longerindirectalignmentwiththeshoulders.

90. INTERNAL ROTATION CONTD…
•Theanteroposteriordiameteroftheheadnowliesinthe
widest(anteroposterior)diameterofthepelvicoutlet.
•Theocciputslipsbeneaththesub-pubicarchandcrowning
occurswhentheheadnolongerrecedesbetweencontraction
andthewidesttransversediameterisborn.
•Offlexionismaintained,thesuboccipitobregmaticdiameter,
usuallydistendsthevaginalorifice.

92. EXTENSION OF THE HEAD
•Oncecrowninghasoccurredthefetalheadcanextend,
pivotingonthesuboccipitalregionaroundthepubicbone.
•Thisreleasesthesinciput,faceandchin,whichsweepthe
perineumandarebornbyamovementofextension.
•Theheadnowextendsuntilitisdelivered.Maximal
distensionoftheperineum&introitusaccompaniesthefinal
expulsionofthehead,aprocessthatisknownascrowning.

93. RESTITUTION
•Thetwistintheneckofthefetusthatresultedfrominternal
rotationisnowcorrectedbyaslightuntwistingmovement.
•Theocciputmovesone-eightofacircletowardsthesidefrom
whichitstarted

94. INTERNAL ROTATION OF THE
SHOULDERS
•Theshouldersundergoasimilar
rotationtothatoftheheadtolieinthe
widestdiameterofthepelvicoutlet,
namelyanteroposterior.
•Theanteriorshoulderisfirsttoreach
thelevatoranimuscleandistherefore
rotatesanteriorlytolieunderthe
symhysispubis.
•Itoccursinthesamedirectionas
restitution,andtheocciputofthefetal
headnowlieslaterally.

95. LATERAL FLEXION-EXTERNAL ROTATION OF
HEAD-EXPULSION OF TRUNK
•Almost immediately after external rotation, the anterior
shoulder slips beneath the subpubic arch and the posterior
shoulder passes over the perineum.
•After delivery of the shoulders, the rest of the body is born by
lateral flexion as the spine bends sideways through the
curved birth canal.

96. SECOND STAGE ENDS WITH DELIVERY
OF BABY.

106. PHYSIOLOGY OF THIRD STAGE OF LABOUR

107. THIRD STAGE OF LABOUR
•Thisstagebeginsimmediatelyafterdeliveryofthe
fetusandinvolvestheseparationandexpulsionofthe
placentaandmembranes,involvingtheseparation,
descentandexpulsionofplacentaandmembranes
andcontrolofhemorrhagefromtheplacentasite.
•Thethirdstageusuallylastsbetween5and15
minutes,butanyperiodupto30minutesisconsidered
tobewithinnormallimits.

108. MECHANICAL FACTORS
•Astheneonateisborn,theuterusspontaneouslycontracts
arounditsdiminishingcontents.
•Theuterinefundusnowliesjustbelowthelevelofthe
umbilicus.
•Thus,bythebeginningofthethirdstage,theplacentalsite
hasalreadydiminishedinareabyabout75%.
•Asthisoccurstheplacentabecomescompressedandthe
bloodintheintervillousspacesisforcedbackintothespongy
layerofthedeciduabasalis.

110. SCHULTZEMETHOD
•Separationusuallybeginscentrallysothatretroplacentalclot
isformed.
•Increasedweighthelpstostriptheadherentlateralborders
andpeelthemembranesofftheuterinewallsothattheclot
thusformedbecomesenclosedinamembranousbagasthe
placentadescends,fetalsurfacefirst.
•Thisprocessofseparationisassociatedwithmoreshearing
ofbothplacentaandmembranesandlessfluidbloodloss.

111. SCHULTZ METHOD

112. MATTHEWS DUNCAN
METHOD
•Theplacentamaybegintoseparateunevenlyatoneofits
lateralborders.
•Thebloodescapessothatseparationisunaidedbythe
formationofaretroplacentalclot.
•Theplacentadescends,slippingsideways,maternalsurface
first.
•Thisprocesstakeslongerandisassociatedwithragged,
incompleteexpulsionofthemembranesandahigherfluid
bloodloss.

114. SEPARATION OF FETAL
MEMBRANES
•Thegreatdecreaseinuterinecavitysurfacearea
simultaneouslythrowsthefetalmembranes—theamnion,
chorionandtheparietaldecidua—intoinnumerablefolds.
•Membranesusuallyremaininsituuntilplacentalseparationis
nearlycompleted.
•Thesearethenpeeledofftheuterinewall,partlybyfurther
contractionofthemyometriumandpartlybytractionthatis
exertedbytheseparatedplacenta,whichliesinthelower
segmentoruppervagina.

115. HOMEOSTASIS
•Retraction of the oblique uterine muscle fibres in the upper
uterine segment through which the tortuous blood vessels
interwine-the resultant thickening of the muscles exert
pressure on the torn vessels, acting as clamps, so securing a
ligature action.

116. HOMEOSTASIS CONT…
•Vigorousuterinecontractionfollowingseparation-thisbrings
thewallsintoappositionsothatfurtherpressureisexertedon
theplacentalsite.
•Thereistransitoryactivationofthecoagulationand
fibrinolyticsystemsduring,andimmediatelyfollowing
placentalseparation

117. SIGNS OF SEPARATION OF PLACENTA
Uterus becomes smaller, harder, more globular & is
below umbilicus on abdominal examination
Uterine height increases & the separated placenta
passes into the lower segment –shroedkarsign
Sudden gush of vaginal bleeding
There is no receding of the umbilical cord on pushing the
uterus upwards with an abdominal hand (kustnersign)

118. placentafollowedbymembranes iseither
deliveredspontaneouslyorbycontrolledcord
tractionmethodfollowedby200-300mlblood
loss.
•Modified Brandt-Andrew’s
Technique (Controlled cord
Traction method)
Crede’s Method

119. MANUAL REMOVAL OF PLACENTA

120. FOURTH STAGE OF LABOUR

121. •Thefirst4hourspostpartum,sometimesreferredtoas4
th
stageoflabor;(stageofobservationforatleast1hourafterthe
deliveryofthebaby,placenta&themembranestoensure
thatvoththemother&thebabyarewell).Itisthetimethat
physiologicstabilityisrestored.
•Duringthisperiodmyometrialcontraction&retraction,
accompaniedbyvesselthrombosis,operateeffectivelyto
controlbleedingfromtheplacentalsite.