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What is polyhydramnios?

Polyhydramnios is a condition that occurs when amniotic fluid levels are higher than expected during pregnancy. Amniotic fluid is the watery substance that surrounds your baby before birth.

Polyhydramnios is most often diagnosed during the second or third trimesters In most cases, polyhydramnios does not cause significant problems. In rare cases it can lead to complications during pregnancy or occur because of a developmental issue.

What causes polyhydramnios?

At least half of all cases of polyhydramnios have no known cause. The rest of the time, polyhydramnios occurs due to issues including:

  • Preexisting medical conditions in the pregnant person, such as diabetes
  • Babies measuring larger than expected
  • Genetic conditions
  • Congenital (present at birth) physical conditions in the baby, especially ones affecting swallowing, digestion, urine production, breathing, blood circulation and the nervous system
  • Problems with the placenta or the baby’s heart rate
  • Complications of multiple gestations, such as twin-twin-transfusion syndrome

What are the risks of too much amniotic fluid?

Generally, the later in pregnancy polyhydramnios occurs, the lower the risk to your baby. Complications of polyhydramnios include:

  • Maternal symptoms caused by increased stretching of the uterus such as abdominal distention, contractions and shortness of breath
  • Preterm premature rupture of the membranes (PPROM), when the amniotic sac breaks before full term
  • Preterm birth
  • Stillbirth
  • Placental abruption, separation of the placenta from the uterus that leads to bleeding
  • Problems during delivery, such as the baby being in a poor position or a prolapsed umbilical cord
  • Postpartum hemorrhage (heavy bleeding after birth)

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