In a third-trimester unresponsive patient with apneic pulseless arrest, which condition is most likely?

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

Answer: (A)

In a third-trimester patient who becomes unresponsive with apnea and pulseless arrest, the scenario most consistent with amniotic fluid embolism. Amniotic fluid embolism occurs when amniotic fluid and fetal debris enter the maternal circulation, triggering a sudden, severe systemic reaction that leads to respiratory failure (apnea), profound hypotension, and often disseminated intravascular coagulation. This rapid cascade can progress directly to cardiac arrest, which is why apnea and pulselessness are characteristic in this context.

The other obstetric emergencies can cause maternal collapse as well, but they tend to present with more distinctive signs: uterine rupture often includes sudden severe abdominal pain and possible loss of fetal monitoring with signs of shock; placental abruption usually presents with vaginal bleeding and abdominal pain; eclampsia centers on seizures. While any of these can lead to arrest, amniotic fluid embolism best fits the sudden, combined respiratory and cardiovascular collapse in a late-pregnancy patient.

Management emphasizes rapid, high-quality CPR and airway/oxygenation, with urgent involvement of obstetric teams and preparedness for coagulopathy management; delivery may be considered as part of definitive care, depending on the clinical situation.