Amniotic fluid embolism (AFE) is a rare but serious complication of pregnancy. It happens when fetal cells or amniotic fluid, which is the fluid surrounding a fetus in the uterus during pregnancy, enters the parent’s bloodstream.

AFE is rare, but it can be life threatening.

It usually occurs during labor or after birth, and it can affect the parent, fetus, or both. Initial symptoms may include shortness of breath, agitation, nausea, and vomiting.

The symptoms can quickly become serious, so a person should seek emergency medical care right away. Prompt treatment can help manage long-term complications and prevent death.

Read on to learn more about the symptoms of AFE, what causes it, risk factors, and more.

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AFE, or anaphylactoid syndrome of pregnancy, is a very rare pregnancy complication.

Research suggests that the condition affects approximately 5.1 deliveries out of 100,000 in the United States. This means that it occurs in around 0.005% of deliveries.

In the uterus, a fetus is surrounded by the amniotic sac, which is filled with fluid that provides support and protection. If amniotic fluid or cells from the fetus enter the parent’s bloodstream, it can block blood flow in an artery. This is called an embolism.

Most instances of AFE occur during or immediately after delivery. They can happen during both cesarian and vaginal deliveries.

In very rare cases, AFE can also occur during or after an abortion.

AFE usually develops suddenly. It affects multiple organ systems around the body, which makes it very dangerous. Without treatment, it can cause heart failure and cardiac arrest.

Some early signs and symptoms include:

Some later symptoms include:

  • seizures
  • loss of consciousness
  • bleeding from the cesarean incision, uterus, or intravenous sites

AFE is considered an emergency, so treatment is prompt and aggressive. Researchers note that early recognition of AFE is important to a positive outcome for both the parent and the fetus.

Initially, healthcare professionals will stabilize the parent and, if necessary, deliver the fetus.

Treatment for the parent may involve stabilizing their heart function and breathing. This can include:

  • delivery of supplemental oxygen
  • cardiopulmonary resuscitation, which is a technique that restarts an individual’s heartbeat, breathing, or both
  • use of a ventilator, which is a mechanical device that helps a person breathe

Healthcare professionals may also administer medications to help maintain the person’s blood pressure and reduce fluid in the lungs and around the heart.

When a person is in labor, amniotic fluid or fetal cells can enter the bloodstream. In many cases, this causes no problems.

However, some people’s immune systems react badly to these cells. They treat them as a foreign substance, thereby triggering an allergic reaction. This causes overwhelming inflammation, causing an embolism and harming healthy tissues.

In most cases, the amniotic fluid and fetal cells stem from small tears in the cervix. They can also come from damage to or anomalies in the placenta, which is the organ connecting the fetus to the parent.

Certain individuals are at higher risk of experiencing AFE. According to one 2016 paper, parents are more at risk if they:

  • are older
  • have intense contractions during labor
  • have had five or more pregnancies
  • have a cesarean delivery
  • have induced labor
  • are having multiple babies
  • have tears in the cervix or uterus

Some pregnancy-related complications increase a person’s risk of AFE. These include:

  • placenta previa, which is a condition wherein the placenta partially or completely blocks the cervix
  • eclampsia, which is a condition involving high blood pressure that triggers convulsions, often followed by a coma
  • early separation of the placenta from the wall of the uterus
  • fetal distress or death

Although some factors may increase a person’s risk of AFE, there are no clear warning signs of the condition. It is currently impossible to predict, anticipate, or prevent.

Healthcare professionals know that the condition happens because of an immune response, but they do not understand why it affects some people and not others.

People giving birth in a hospital can receive immediate medical care when they experience symptoms of AFE.

However, if a person is having a home birth, has gone into labor, or has returned home after giving birth, they should be aware of the early symptoms of the condition. They should call 911 and seek emergency medical attention if they think they may be experiencing AFE.

Early treatment may be life saving, and it can help prevent long-term complications.

AFE is a dangerous, and sometimes fatal, condition. Statistics on parental and fetal survival rates vary, but they do reveal the serious nature of the complication.

Outlook for the parent

One article from 2021 reports that the death rates of parents who experience AFE are in the range of 40–60%.

The outlook is better if a person receives an early diagnosis and prompt treatment. However, about two-thirds of people who survive AFE will have lung, neurological, and cardiovascular impairments.

Although researchers do not know the risk of AFE reoccurrence, there are some reports of people having healthy future pregnancies.

People who have experienced AFE and who want to get pregnant again may wish to contact a doctor.

Outlook for the fetus

The death rate for the fetuses involved in AFE is about 30%. However, those who survive tend to have a high rate of:

  • cognitive disabilities, which are conditions affecting one’s ability to think
  • cerebral palsy, which is a condition involving poor muscle coordination
  • hypoxic-ischemic encephalopathy, which is a brain condition that happens when the brain goes too long without oxygen

AFE is a rare but serious condition. It occurs when amniotic fluid or fetal cells enter the parent’s bloodstream, causing a blockage.

There is no known way to prevent the condition, but maternal risk factors include older age, having a pregnancy with more than one fetus, and having a cesarean delivery.

AFE is considered an emergency, so people with any symptoms of the condition need immediate medical attention.