Which condition may present with sudden respiratory distress and cyanosis in a third-trimester patient?

• A. Amniotic fluid embolism
• B. Uterine rupture
• C. Abruptio placentae
• D. Eclampsia

Answer: (A)

Sudden respiratory distress with cyanosis in a third-trimester patient points to amniotic fluid embolism. This condition happens when amniotic fluid or fetal debris enters the maternal circulation, triggering an abrupt, systemic reaction that affects the lungs and circulation. The result is rapid hypoxemia, difficulty breathing, and often cyanosis, followed quickly by hypotension and potential coagulopathy. It can occur during labor, delivery, or soon after.

Other obstetric emergencies have different hallmark features. Uterine rupture typically presents with sudden abdominal or chest pain, loss of fetal heart tones, and often vaginal bleeding, rather than immediate respiratory collapse. Abruptio placentae usually shows painful vaginal bleeding with a rigid tender uterus and signs of fetal distress. Eclampsia centers on severe hypertension with seizures and possible pulmonary edema, but the classic immediate presentation is not sudden cyanosis from a primary pulmonary event.

So the combination of sudden respiratory distress and cyanosis in this context most strongly aligns with amniotic fluid embolism.