Excess amniotic fluid (more than 2 litres at term), commonly due to foetal anomalies. There are two clinical situations:
– In the second trimester: acute polyhydramnios;
– In the third trimester: chronic polyhydramnios.
4.8.1 Acute polyhydramnios (rare but serious)
– Rapid increase in the size of the uterus
– Painful abdomen, abdominal pressure, dyspnoea
– Distended, hard uterus, foetus cannot be palpated
Usually associated with foetal malformation, sometimes a complicated twin pregnancy.
Do not intervene; let the patient abort or deliver spontaneously.
4.8.2 Chronic polyhydramnios
– More moderate increase in the size of the uterus, occurring in spurts
– Foetus cannot be palpated
– Receding head on vaginal examination, fluid wave
– Foetal heartbeat muffled
– Look for diabetes and treat if found.
– Examine the neonate for malformation.
– Risk of neonatal hypoglycaemia (Chapter 10, Section 10.3.4).
In acute and chronic polyhydramnios:
– Do not puncture or drain amniotic fluid during pregnancy: risk of infection.
– Use of oxytocin during labour is dangerous and oxytocin should be administered with caution as the over-distended uterus may rupture.
– Amniotomy carries risk of cord prolapse. In the event of cord prolapse, a caesarean section may be considered taking into account gestational age and potential presence of foetal malformation. In the event of acute polyhydramnios in the second trimester, perform vaginal delivery.
– Risk of postpartum haemorrhage (routinely insert an IV line).