Presence of too much amniotic fluid in the uterus

Aetiology

Causes of polyhydramnios can be due to excessive production of amniotic fluid or insufficient removal of amniotic fluid.

Excess production can be due to increased foetal urination:

• Maternal diabetes mellitus
• Foetal renal disorders
• Foetal anaemia
• Twin-to-twin transfusion syndrome

Insufficient removal can be due to reduced foetal swallowing:

• Oesophageal or duodenal atresia
• Diaphragmatic hernia
• Anencephaly
• Chromosomal disorders

DITCH (diabetes, idiopathic/infection, congenital abnormalities, heart failure)

Clinical features

Polyhydramnios may present with a uterus which feels tense or large for dates and it may be difficult to feel the foetal parts on palpation of the abdomen. In many cases of polyhydramnios there is no identifiable cause.

Management

Treatment includes management of any underlying causes (e.g. in maternal diabetes) and amnio-reduction in severe cases.

• NSAIDS (indomethacin) - reduce foetal urine output due to prostaglandin inhibition