Amniotic fluid

1. AMNIOTIC FLUID Fahad zakwan

2. Amniotic fluid formation and composition: First & early second trimester: Amount is 5-50 ml & arises from: ultrafiltrate of Maternal plasma through the vascularized uterine decidua (in early pregnancy). Transudation of fetal plasma through the fetal skin & umbilical cord (up to 20 weeks' gestation ). * It is iso-osmolar with fetal & maternal plasma, though it is devoid of proteins .

3. Volume and composition From 20 weeks up to term ( mainly fetal urine ): At 18th week, the fetus voids 7-14ml/day; at term fetal kidneys secretes 600-700ml of urine/day into AF. Fetal respiratory tract secretes 250ml/day into AF. Fluid transfers across the placenta. Fetal oro-nasal secretions. Secretion is controlled by: - Fetal swallowing at term removes 500ml/day. - Reabsorption into maternal plasma (osmotic gradient). AF constituents: - urea, creatinine & uric acid + desquamated fetal cells, vernix , lanugo hair & others→ hypo- osmolar amniotic fluid….

4. Amniotic fluid circulation

5. Amniotic fluid volume : About 500mls enter and leave the amniotic sac each hour. gradual ↑ up to 36 weeks to around 600 to 1000 ml then ↓ after that. The normal range is wide but the approximate volumes are: - 500 ml at 18 weeks - 800 ml at 34 weeks. - 600 ml at term .

6. Amniotic fluid function: Allow room for fetal growth, movement and development. Ingestion into GIT → growth and maturation . Fetal pulmonary development (20 weeks). Protects the fetus from trauma. Maintains temperature. Contains antibacterial activity . Aids dilatation of the cervix during labour.

7. Clinical importance of AF: Screening for fetal malformation (serum α - fetoprotien ). Assessment of fetal well-being (amniotic fluid index). Assessment of fetal lung maturity (L/S ratio). Diagnosis and follow up of labour. Diagnosis of PROM (ferning test).

8. Amniotic fluid volume assessment Clinical assessment is unreliable. Objective assessment depends on U/S to measure: - deepest vertical pool (DVP). - Amniotic fluid index (AFI). It is a total of the DVPs in each four quadrants of the uterus. it is a more sensitive indicator of AFV throughout pregnancy.

9. Amniotic fluid abnormalities Oligohydramnios : Defined as reduced amniotic fluid of 200ml or less i.e . amniotic fluid index of 5 cm or less or the deepest vertical pool < 2 cm . Polyhydramnios : Defined as excessive amount of amniotic fluid of 2000ml or more (AFI of > 25 cm or the deepest vertical pool of > 8 cm ) .

10. POLYHYDROMNIOUS

11. Polyhydramnios

12. types Mild hydramnios (80%): a pocket of amniotic fluid measuring 8 to 11 cm. 2. moderate hydramnios (15%): a pocket of amniotic fluid measuring 12 to 15 cm. 3. Severe hydramnios (5%) - twin-twin transfusion syndrome : a pocket of amniotic fluid measuring 16 cm or more .

13. ETIOLOGY OF POLYHYDRAMNIOS Idiopathic Fetal Anomalies Diabetes Multifetal gestation Immune/Non-immune hydrops Fetal infection Placental haemangiomas

14. Fetal Anomalies Problems with swallowing and GI absorption Increased transudation of fluid : anencephaly , spina bifida Increased urination: anencephaly (lack of ADH, stimulation of urination centers) Decreased inspiration

15. SYMPTOMS Dyspnea Abdominal pain Venous stasis Contractions  preterm labor Decreased Perception of Fetal Movements

16. diagnosis of polyhydramnios Symptoms: - dyspnea. - edema. - abdominal distention - preterm labour. Abdominal examination: - ↑uterus than expected. - difficult to palpate fetal parts. - difficult to hear fetal heart sound. - ballotable fetus . - Decreased fetal mov’t Ultrasound: - excessive amniotic fluid. - fetal abnormalities.

17. COMPLICATIONS ( fetus)? Fetal prognosis worsens with more severe hydramnios and congenital anomalies 15-20% fetal malformations Preterm delivery Suspect diabetes Prolapse of cord Abruption

18. (Mother)? Dyspnea Venous Stasis Placental abruption Uterine atony PPH Abnormal presentation -- C/S

19. TREATMENT Mild to Moderate hydramnios: rarely requires treatment Hospitalization, bed rest Amniocentesis NSAIDs Blood sugar control

20. OLIGOHYDRAMNIOS

21. DEFINITION reduced amniotic fluid <200mls i.e . amniotic fluid index of 5 cm or less or the deepest vertical pool < 2 cm .

22. AETIOLOGY FETAL PROM (50%) CHROMOSOMAL ANOMALIES CONGENITAL ANOMALIES IUGR IUFD POSTTERM PREGNANCY MATERNAL PREECLAMPSIA APLA SYNDROME CHRONIC HT PLACENTAL CHRONIC ABRUPTION TTTS CVS DRUGS PG SYNTHETASE INHIBITORS ACE INHIBITORS IDIOPATHIC

23. Complications of oligohydramnios: In early pregnancy: Amniotic adhesions or bands → amputation/death . Pressure deformities (club feet). Pulmonary hypoplasia: - Thoracic compression. - No breathing movement. - No amniotic fluid retain. Flattened face. Postural deformities.

24. In late pregnancy: Fetal growth restriction. Placental abruption. Preterm labour. Fetal distress. Fetal death. Meconium aspiration. Labour induction/CS.

25. Extremely poor fetal prognosis, especially in early pregnancy Adhesions between amnion and fetal parts --- malformations and amputations Musculoskeletal deformities Pulmonary hypoplasia Cord Compression -- >fetal hypoxia Passage of meconium into low AF volume: thick particulate suspension -->respiratory compromise

26. management Minor degrees: no treatment. Bed rest, diuretics, water and salt restriction: ineffective. Hospitalization : dyspnea, abdominal pain or difficult ambulation. Endomethacin therapy: . - impairs lung liquid production/enhances absorption. - ↓fluid movement across fetal membranes. * complications: premature closure of ductus arteriosus, impairment of renal function, and cerebral vasoconstriction. So not used after 35 weeks Amniocentesis : to relieve maternal distress and to test for fetal lung maturity. Complications: ruptured membrane, chorioamnionitis, placental abruption, preterm labour .

27. Dr Mona Shroff www.obgyntoday.info 32

28. TREATMENT ADEQUATE REST – decreases dehydration HYDRATION – Oral/IV Hypotonic fluids(2 Lit/d) temporary increase helpful during labour , SERIAL USG – Monitor growth , AFI, BPP INDUCTION OF LABOUR/ LSCS Lung maturity attained Lethal malformation Fetal jeopardy Severe IUGR Severe oligohydramnios AMNIOINFUSION

29. AMNIOINFUSION INDICATIONS 1.Diagnostic 2.Prophylactic 3.Therapeutic Decreases cord compression Dilutes meconium