Skip to Content

Amniotic Fluid Embolism


Julie S. Moldenhauer

, MD, Children's Hospital of Philadelphia

Last full review/revision Jan 2020| Content last modified Jan 2020

Amniotic fluid embolism occurs when some amniotic fluid (the fluid that surrounds the fetus in the uterus) that contains cells or tissue from the fetus enters the woman’s bloodstream and causes a serious reaction in the woman. This reaction can damage the lungs and heart and cause excessive bleeding.

Amniotic fluid embolism is very rare. It usually occurs during late pregnancy but may occur when an abortion is done during the 1st or 2nd trimester.

Risk is increased when

The fluid or tissue can cause a serious reaction in the woman. The reaction usually occurs during or shortly after labor and delivery. The woman may have a rapid heart rate, an irregular heart rhythm, low blood pressure, and difficulty breathing. She may stop breathing (respiratory failure), or her heart may stop (cardiac arrest). About 20% of women with amniotic fluid embolism die.

Disseminated intravascular coagulation is a common complication. In this disorder, small blood clots develop throughout the bloodstream, resulting in widespread bleeding with massive loss of blood. Emergency care is required.

Prompt diagnosis and treatment of amniotic fluid embolism are essential. Doctors diagnose this problem based on symptoms, particularly when a woman has the following three symptoms:

  • Sudden difficulty breathing
  • Low blood pressure
  • Widespread, uncontrolled bleeding

Women may be given a transfusion of blood and blood components. Injection of a blood clotting factor (which helps blood clot) may be lifesaving. Women may require assistance with breathing or drugs to help the heart contract.

The baby may be delivered immediately using forceps or a vacuum extractor, or cesarean delivery may be done. Such a delivery does not appear to improve or worsen the woman's outcome. However, it may be lifesaving for the fetus if the fetus is old enough to survive outside the uterus.

Copyright © 2021 Merck & Co., Inc., known as MSD outside of the US, Kenilworth, New Jersey, USA. All rights reserved. Merck Manual Disclaimer