Blocking of maternal circulation by amniotic fluid that is forced into uterine veins by strong uterine contraction near the end of pregnancy. it is characterized by the sudden onset of severe respiratory distress and hypotension that can lead to maternal death.

An amniotic fluid embolism (AFE) is a life-threatening childbirth (obstetric) emergency in which amniotic fluid enters the blood stream of the mother, triggering a serious reaction which results in cardiorespiratory (heart and lung) collapse and massive bleeding (coagulopathy). The rate at which it occurs is 1 instance per 20,000 births and it comprises 10% of all maternal deaths..