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

Amniotic fluid surrounds and cushions the infant throughout development. There may be too little or too much amniotic fluid due to problems in the fetus.

Polyhydramnios can occur if the fetus does not swallow and absorb amniotic fluid in normal amounts. This can happen due to gastrointestinal disorders, brain and nervous system (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.

• Achondroplasia
• Anencephaly
• Beckwith-Wiedemann syndrome
• Diaphragmatic hernia
• Duodenal atresia
• Esophageal atresia
• Gastroschisis
• Gestational diabetes
• Hydrops fetalis
• Multiple gestation (for example, twins or triplets)

This condition is discovered during pregnancy, and evaluated before delivery. If the health care provider finds a fetal abnormality, 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