ABSTRACT

Polyhydramnios is caused by reduced fetal swallowing or increased fetal urine production. This occurs in 0.5%–1% of pregnancies. Amniodrainage for polyhydramnios is aimed at reducing the risk of pre-term delivery and improving maternal discomfort. As with all defects, targeted detailed ultrasound for associated abnormalities should be performed. The most common associated defects are gastrointestinal or central nervous system abnormalities. The presence of multiple abnormalities or abnormalities that do not explain the polyhydramnios should raise the suspicion of an underlying chromosomal or genetic syndrome. Absent or greatly reduced fetal movement can be suggestive of a neuromuscular disorder. Careful examination of the fetal heart including the heart rhythm should be performed in order to exclude conditions such as fetal supraventricular tachycardia or heart block. Many fetal arrhythmias can be treated by maternal administration of an anti-arrhythmic drug.