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).

PROM: Premature rupture of membranes

• 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

Normal amniotic fluid volume

Amniotic fluid volume (AFV) assessment

• Clinical assessment is unreliable.• Objective assessment depends on U/S to

measure:

Deepest vertical pool (DVP) &

Amniotic fluid index (AFI)

Signs/symptoms

• Fundal height < gestational age• Decreased fetal movement• Fetal Heart Rate tracing abnormality• Diagnosis: Ultrasound

2. Maternal causes:• Uteroplacental insufficiency.• Preeclampsia.

3. Placental causes:• twin-twin transfusion.

4. Drug causes: Prostaglandin synthase inhibitor as NSAID.

5. Idiopathic

Causes of oligohydramnios

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.

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

Complications of oligohydramnios

Low level of nitric oxide (NO) plays an important role in the pathogenesis of

pregnancy complications and other diseases.

J Obstet Gynaecol Res. 2010 Apr;36(2):239-47 Free Radic Biol Med. 2010 Aug 1;49(3):493-500

Pflugers Arch. 2010 May;459(6):841-51Int J Gynaecol Obstet. 2005 Jan;88(1):15-8

A recent research ………

The endothelium (inner lining) of blood vessels uses nitric oxide to relax smooth muscle, thus resulting in vasodilation and increasing blood flow

NO causes vasodilation & increasing blood flow

L-Arginine may be a useful treatment in Oligohydramnios

Polyhydramnios

Causes of polyhydramnios

• Fetal malformation: - GIT: esophageal/duodenal

atresia, tracheoesophageal fistula.

- CNS: anencephaly (↓swallowing, exposed meninges, no antidiuretic hormone).

• Twin-twin transfusion → fetal polyuria.

• Hydrops fetalis: congestive heart failure, severe anaemia or hypoproteinemia → placental transudation

• Diabetes mellitus (osmotic diuresis).

• Idiopathic.

(fetus)?• Fetal prognosis worsens with more severe

hydramnios and congenital anomalies• 15-20% fetal malformations• Preterm delivery• Suspect diabetes• Prolapse of cord• Abruption

(Mother)?

• Dyspnea• Venous Stasis• Placental abruption• Uterine dysfunction• Post-partum hemorrhage• Abnormal presentation -- C/S

Management of polyhydramnios• Minor degrees: no treatment.• Bed rest, diuretics, water and salt restriction: ineffective.• Hospitalization: dyspnea, abdominal pain or difficult

ambulation.• Indomethacin 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. • Amniocentesis: to relieve maternal distress and to test for fetal

lung maturity. Complications: ruptured membrane, chorioamnionitis, placental abruption, preterm labour.