Polyhydramnios

Diagnosis

Polyhydramnios is usually diagnosed with a fetal ultrasound, which uses high-frequency sound waves to create images of your unborn baby.

Health care professionals assess amniotic fluid levels by measuring:
• The single largest pocket of fluid around the baby, called the maximum vertical pocket (MVP)
• The fluid in all four quadrants of the uterus, called the amniotic fluid index (AFI)

Polyhydramnios is diagnosed if the MVP is 8 centimeters or greater, or the AFI is 24 centimeters or greater.

Additional tests may be recommended to determine the cause:
• Blood tests to check for infections linked with polyhydramnios
• Amniocentesis to analyze amniotic fluid for fetal cells, chemicals, and potential genetic disorders

Monitoring during pregnancy may include:
• Nonstress test to track the baby’s heart rate response to movement
• Biophysical profile, which uses ultrasound to assess fetal breathing, movement, and amniotic fluid volume, sometimes combined with a nonstress test

Treatment

Mild polyhydramnios often resolves on its own and may not require treatment.

Treatment focuses on addressing any underlying cause, such as diabetes, and may include:

Hospital treatment for severe polyhydramnios
• Drainage of extra amniotic fluid through amniocentesis, which carries a small risk of preterm labor, placental abruption, or premature rupture of membranes
• Medicine such as indomethacin, taken orally for up to 48 hours, to reduce contractions and amniotic fluid volume

After treatment, amniotic fluid levels are typically checked every 1 to 3 weeks.

Delivery planning
• Mild to moderate polyhydramnios: delivery is often planned at 39–40 weeks
• Severe polyhydramnios: timing of delivery is carefully planned to reduce risks for mother and baby

Close coordination with your health care team helps ensure safe management of polyhydramnios for both you and your baby.