Polyhydramnios and oligohydramnios

1.  Polyhydramnios
 Definition: an excess of amniotic fluid detected
clinically. The range of normal volumes of fluid
present is wide and varies with the duration of
pregnancy.
Average values for amniotic fluid are:
12 weeks: 50ml;
24 weeks: 500ml;
36 weeks: 1000ml;
 The normal range at term in a singleton
pregnancy is large—500–1500ml.
 Diagnosis:- This is either clinical or by simple
ultrasound. Other methods of measuring
amniotic fluid in situ are too complex for routine
use and often unreliable.
 History
Tenseness of abdomen.
Unable to lie comfortably in any position.
Dyspnoea, indigestion, piles and varicose veins.
Decreased sensation of fetal movements.
 Examination
 Increased symphysio-fundal height.
 Very tense, cystic uterus bigger than
maturity (like a balloon filled with water).
 Difficult to feel any fetal parts.

2.  Investigations
Ultrasound. The deepest column >8cm or the
amniotic
fluid index is greater than the 95th centile.
 Differential diagnosis
 Twins: laxer feel to uterus and too many
fetal parts felt.
 Ovarian cyst: uterus displaced to one
side in later
 pregnancy.
 Full bladder.
 All are resolved by ultrasound
examination.
Associations
 MATERNAL
• Diabetes.
 FETAL
• Congenital abnormality; anencephaly;
 meningomyelocoele; upper alimentary atresia
e.g.
 tracheoesophageal fistula.
• Twins (particularly monozygotic).
 Clinical course
 ACUTE

3. • Painful with tense uterus and oedematous
abdominal wall.
• Primiparous.
• Pre-eclampsia.
• Often early (22–32 weeks’ gestation).
 CHRONIC
• Slower onset.
• Uncomfortable rather than painful.
• Last weeks of pregnancy.
 Management
 ACUTE
1 Bed rest.
2 Ultrasound to rule out twins or abnormality.
3 Release fluid from uterus.
If fetus normal: through abdominal wall with
 narrow-bore needle. Drain fluid off slowly until
the woman is comfortable (500–1000ml over 4–
8 hours).
• If fetus abnormal and viable—consider
induction.
 If not viable—paracentesis.
 CHRONIC
1 Bed rest.
2 Ultrasound to rule out twins and fetal abnormality.
3 Glucose tolerance test.

4. 4 Sedation if very painful.Treat underlying maternal
condition.
5 If fetus normal, induce labour when indicated by
fetal state not because of the polyhydramnios. Watch
for uterine dysfunction and postpartum haemorrhage
(PPH) after labour.
 Oligohydramnios
 A lack of amniotic fluid, a much rarer
 condition.
 Diagnosis
• Uterus is small for dates (early).
• Uterus feels full of fetus (later).
• Ultrasound shows reduced amniotic fluid
index
 (<2cm columns).
 Fetal associations
• Adhesions from fetal skin to amnion.
• Renal agenesis.
• Asymmetrical SGA.
 Clinical course
• Labour often preterm.
• High fetal death rate.
• High rate of fetal