Polyhydramnios is the presence of excessive amniotic fluid surrounding the unborn infant.


Amniotic fluid surrounds and cushions the infant throughout development. Decreased or excessive amounts of amniotic fluid may be associated with abnormalities in the fetus.

Polyhydramnios may be from failure by the fetus to swallow and absorb amniotic fluid in normal amounts. This may occur as a result of gastrointestinal disorders, neurological problems, or a variety of other causes. Polyhydramnios may also be related to increased fluid production, as is the case with certain fetal lung disorders.

Sometimes, no specific cause for polyhydramnios is found.

Common Causes

  • esophageal atresia  
  • duodenal atresia  
  • anencephaly  
  • hydrops fetalis  
  • achondroplasia  
  • Beckwith-Wiedemann syndrome  
  • diaphragmatic hernia  
  • gastroschisis  
  • multifetal gestations (for example, twins or triplets)  
  • gestational diabetes

What to expect at your health care provider’s office

This condition is discovered during pregnancy, and evaluated prior to delivery. If a fetal abnormality is found, the baby will be delivered in a hospital with specialists who can provide immediate evaluation and treatment.

Documenting polyhydramnios may include:

  • history of this pregnancy  
  • history of past pregnancies and health of the children delivered  
  • other family history  
  • ultrasound scans of the fetus

Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

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