Amniotic Fluid Embolism

An amniotic fluid embolism (AFE) can be a devastating blow to what was supposed to be a joyful experience. While AFE is unpredictable, unpreventable, and can be a life-threatening pregnancy complication, it is also very rare—occurring in only one out of every 21,000 pregnancies—but it may be useful to at least have heard of it.

In a normal patient, amniotic fluid doesn’t enter the maternal circulation system; it remains safely contained inside the uterus, sealed off by the amniotic sac. AFE occurs when the barrier between the amniotic fluid and maternal circulation is broken, and the amniotic fluid enters the mother’s venous system. The most likely time for this thankfully very rare event to occur is during delivery, or during a pregnancy termination. Something happens suddenly that allows some amniotic fluid (which contains many different chemicals, hormones, and fetal skin cells) to enter the mother’s veins and then circulate in her blood stream. The effect is like giving a pregnant woman a transfusion of a large volume of amniotic fluid.

The reason why this occurs in some women and not others is still not well understood. When it happens, a doctor has no more than three minutes to notice symptoms, properly diagnose the problem, and react.

There are two phases of AFE. During phase one, the patient begins to experience shortness of breath and a sudden drop in blood pressure (hypotension). Cardiac arrest can quickly follow, as the chambers of the heart do not get enough blood to circulate to the body. Most patients lapse into a coma within moments, and 60–80 percent of patients do not survive long enough to make it through this first phase of amniotic fluid embolism.

Those patients who do survive enter the second phase of AFE, the hemorrhagic phase, which is often accompanied by severe shortness of breath, shivering, coughing, vomiting, and excessive bleeding due to a condition called DIC (disseminated intravascular coagulation). DIC causes blood to leak from the body because it can no longer clot. The low blood pressure leads to cardio-vascular collapse, which causes fetal distress and can lead to the death of the infant if he or she is not delivered immediately.

This condition is truly devastating, and there are no warning signs. There are no known prevention or treatment methods, and because there are no diagnostic tests available, experts rely on the following symptoms to diagnose a patient:

  • Acute shortness of breath and hypoxia (low blood oxygen)
  • Sudden onset of severe chest pain
  • Acute hypotension (sudden drop in blood pressure) or cardiac arrest
  • Severe hemorrhage from multiple body sites in the absence of other explanations
  • Seizure
  • All of the above occurring during labor, caesarean deliveries, dilation and evacuation, or within 30 minutes postpartum without any other explanation

Amniotic Fluid Embolism Facts

Here are some facts about this mysterious condition:

  • AFE does not discriminate by race or age
  • AFE can occur during an abortion
  • It is believed to occur in one in 21,000 pregnancies
  • Fatalities occur in 61 percent of all cases in the US
  • 50 percent of victims die within the first hour of the onset of symptoms
  • Survival is uncommon
  • Survivors can suffer from permanent neurologic impairments (from oxygen deprivation)
  • There is an increased risk in women over the age of 30
  • No diagnostic test exists today

Amniotic Fluid Embolism Symptoms

Experts still disagree on what symptoms to watch for, since in up to 80 percent of all cases, the diagnosis isn’t made until after the death of the mother and/or infant. Still, the symptoms listed below are common enough that most experts agree that they are likely due to AFE. However, most experts still believe that AFE cannot be predicted or prevented.

  • Hypotension (severe low blood pressure)
  • Dyspnea (shortness of breath)
  • Seizure
  • Cough
  • Slow fetal heartbeat (fetal bradycardia or fetal distress)
  • Cardiac arrest (heart attack)
  • Shock (severe drop in blood pressure)
  • Cyanosis (blue skin caused by being in shock)
  • Pulmonary edema (lungs fill with fluid and fail to deliver oxygen to the blood)
  • Confusion or Loss of consciousness
  • Hemorrhaging (especially from IV sites, vaginal area, or mouth or nose)

Amniotic Fluid Embolism Causes

Experts believe one or more of the following has to happen for AFE to occur:

  • Ruptured membranes
  • Ruptured uterine or cervical veins
  • A pressure gradient from uterus to maternal veins
  • Abdominal trauma during pregnancy

Again, there is no scientific proof that any of these is the cause for AFE, but now that more and more people are becoming aware of the condition, extensive research is being conducted.

Other Conditions to Consider

When a pregnant woman during labor, Cesarean section, or pregnancy termination develops sudden shortness of breath with a drop in blood pressure, AFE is one of the possible causes, but others need to be considered and quickly ruled in or ruled out. Other causes include pulmonary embolism, acute myocardial infarction (heart attack), acute heart failure, anaphylactic reaction to a medication or sudden profound hemorrhage (rapid loss of large volume of blood). Each of these is potentially life-threatening, but they are all managed differently.

Amniotic Fluid Embolism Treatment

Treatment includes supplemental oxygen (and usually placement on a ventilator), large volume of intravenous fluids, transfusion of blood and blood products, medications to raise blood pressure, and usually immediate delivery of the baby if delivery has not already occurred. If a patient survives the first phase she should be placed on life support and moved into an intensive care unit for around-the-clock supervision.

This page was last updated on 06/2017

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