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Amniotic Fluid Embolism

By

Julie S. Moldenhauer

, MD, Children's Hospital of Philadelphia

Last full review/revision Jul 2021| Content last modified Jul 2021

Amniotic fluid embolism occurs when some amniotic fluid that contains cells or tissue from the fetus enters the woman’s bloodstream and causes a serious reaction in the woman. (Amniotic fluid is the fluid that surrounds the fetus in the uterus.) 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 factors

Many women are exposed to cells and tissues from the fetus during labor and delivery, and the conditions that increase risk are much more common than amniotic fluid embolism. Thus, it is unclear why amniotic fluid embolism develops in some women and not others.

Risk is increased when

Symptoms

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.

Diagnosis

  • A doctor's evaluation

Prompt diagnosis and treatment of amniotic fluid embolism are essential.

Doctors diagnose amniotic fluid embolism based on symptoms, particularly when a woman has the following symptoms:

  • Sudden stopping of the heart
  • Sudden difficulty breathing
  • Low blood pressure
  • Widespread, uncontrolled bleeding

Treatment

  • Supportive care

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.

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