Amniotic Fluid Embolism occurs when amniotic fluid, fetal cells, hair, or other materials enter the blood system of a pregnant woman. usually via tears in the uterus or cervix during labor and delivery, or through partial separation of the placenta.

Amniotic fluid embolism (AFE) is a very rare and life threatening complication during pregnancy or childbirth, occuring in about  less than 1 in 50,000 pregnancies. In one case series, the mortality rate was 20% or 1 in 5 women with amniotic fluid embolism.

The exact cause of amniotic fluid embolism is unknown. It can happen when amniotic fluid enters the blood circulation of the pregnant woman, and subsequently there is a spasm (narrowing) of the pulmonary (lung) blood vessels, interrupting normal blood supply through the heart and lungs. This can lead to hypoxia, a low oxygen status which causes damage to heart and lung vessels, leading to ARDS (Acute Respiratory Distress Syndrome) and failure of respiration. Subsequently, women may lose large amounts of blood due to coagulopathy  (abnormal clotting of the blood). 

Signs of amniotic fluid embolism (AFE)

Signs of AFE include sudden shortness of breath and hypotension (low blood pressure). This can be followed by heart failure and seizures with massive bleeding associated with abnormal blood clotting (coagulopathy).

When does amniotic fluid embolism happen?

Amniotic Fluid Embolism can occur in otherwise healthy women

• during labor,
• during caesarean section,
• after vaginal delivery, or
• during the second trimester of pregnancy.
• it may also occur up to 48 hours post delivery.

Risk Factors for amniotic fluid embolism

• Older maternal age
• Caesarean section
• Multiparity (more than one child)
• Labor induction
• Fetal distress
• Fetal death
• Male baby
• Intense contractions
• Abdominal trauma
• Tears in the uterus or cervix
• Early separation of the placenta from the uterus wall
• Intestinal material from the foetus entering the woman’s blood stream

Treatment of amniotic fluid embolism

Most treatment addresses individual symptoms. Cardiopulmonary resuscitation (CPR) and blood product transfusions may be required. If the woman is still pregnant, the fetus is usually monitored closely for signs of distress.