Topic Overview

Polyhydramnios is a condition in which there is too much fluid in the amniotic sac, the sac that holds the developing baby (fetus). This liquid is called amniotic fluid, and it surrounds the fetus throughout pregnancy.

Polyhydramnios can be caused by:

  • Problems with the baby's nervous system or gastrointestinal tract.
  • Genetic disorders or birth defects.
  • Multiple pregnancy (twins or more). It occurs in up to 5 out of 100 twin pregnancies.footnote 1
  • Diabetes.

Sometimes the cause of polyhydramnios may not be found.

Polyhydramnios increases the risk of:

  • Premature breaking (rupture) of the amniotic sac.
  • Premature labor.
  • Stillbirth.

Severe polyhydramnios may be treated with medicine, such as indomethacin. Excess fluid is sometimes removed through a needle that is inserted through the mother's abdomen into the amniotic sac (amniocentesis).



  1. Newman RB, Rittenberg C (2008). Multiple gestations. In RS Gibbs et al., eds., Danforth's Obstetrics and Gynecology, 10th ed., pp. 220–245. Philadelphia: Lippincott Williams and Wilkins.


ByHealthwise Staff
Primary Medical ReviewerSarah Marshall, MD - Family Medicine
Specialist Medical ReviewerWilliam Gilbert, MD - Maternal and Fetal Medicine

Current as ofMay 22, 2015