<s>[INST] context: The question has been discussed in many ways since the exact choice asked was not recalled properly: In the aforementioned format, The most frequent cause of obstetrical hemorrhage is failure of the uterus to contract sufficiently after delivery and to arrest bleeding from vessels at the placental implantation site Data from Al-Zirqi, 2008; Berg, 2010; Chichakli, 1999; Zwa, 2008 If the question was 'sudden un explained death', then an amniotic fluid embolism can be the answer The true incidence of AFE is unknown, but has been repoed to range from 1:8 000 to 1:80 000 pregnancies. Amniotic fluid embolism (AFE) it as a syndrome of sudden peripaum shock. This is a catastrophic obstetric emergency that can present as sudden, profound, and unexpected maternal collapse associated with hypotension, hypoxaemia, and disseminated intravascular coagulation (DIC). It occurs when amniotic fluid, fetal cells, hair, or other debris enter the maternal circulation. Risk Factors: Advanced maternal age; multiparity; meconium stained liquor; intrauterine fetal death; polyhydramnios; strong frequent or tetanic uterine contractions; maternal history of allergy or atopy; chorioamnionitis; AFE is caused by fetal antigens in the amniotic fluid stimulating a cascade of endogenous immune mediators, producing a reaction similar to anaphylaxis [/INST] question: Which of the following is the most likely cause of a woman presenting with shock in immediate post paum period | options: A: PPH B: Post paum eclampsia C: Uterine inversion D: Amniotic fluid embolus | answer: A </s>