Amniotic fluid embolism (AFE) is a rare obstetric emergency in which amniotic fluid, fetal cells, hair, or other debris enters the mother's blood stream via the placental bed of the uterus and trigger an allergic reaction. Amniotic fluid probably enters the maternal circulation through the endocervical veins, the placental insertion site, or a site of uterine trauma. Once it reaches the maternal circulation, it can precipitate cardiogenic shock, respiratory failure, and, most likely, an inflammatory and anaphylactoid response.Other possible symptoms may also include fetal distress (signs that the baby is unwell including changes in the fetal heart rate or decreased movement in the womb), vomiting, nausea, seizures, severe anxiety, and skin discoloration.
Several factors have been associated with amniotic fluid embolism syndrome. They include precipitous or tumultuous labor, advanced maternal age, cesarean and instrumental delivery, placenta previa and abruption, grand multiparity (≥5 live births or stillbirths), cervical lacerations, fetal distress, eclampsia, and medical induction of labor . Our understanding of the pathogenesis suggests that these factors probably are associated with amniotic fluid embolism syndrome, but not the direct cause. The syndrome is best considered unpredictable and unpreventable.AFE is a diagnosis of exclusion and is made clinically. It requires a high index of suspicion on clinical criteria, as above.
In the first phase, the patient experiences acute shortness of breath and hypotension. This rapidly progresses to cardiac failure leading to a reduction of perfusion to the heart and lungs. This may be accompanied by other "premonitory symptoms" such as shivering, coughing, vomiting, and an unpleasant taste in the mouth. Not long after this stage the patient will lose consciousness due to circulatory collapse. While previously believed to have a maternal mortality rate of 60-80%, more recently it has been reported at 26.4%