Correct Answer: D. Placenta previa
Placenta previa is a condition of abnormal placental implantation in the lower uterine segment, diagnosed during pregnancy on ultrasound. It is a cause of primary PPH (antepartum and intrapartum hemorrhage), not secondary PPH. Secondary PPH occurs in the postpartum period (after delivery of the baby and placenta) and is caused by retained products of conception, endometritis, or placental site pathology. Placenta previa leads to hemorrhage before or during labor due to separation of the abnormally implanted placenta from the lower segment as the cervix dilates. Once the placenta is delivered, placenta previa ceases to be a hemorrhage risk. In contrast, retained cotyledons (remnants of placental tissue), placental polyps (granulation tissue at placental site), and endometritis all persist in the postpartum uterus and cause secondary PPH through impaired uterine contraction, local inflammation, or retained tissue preventing hemostasis. Therefore, placenta previa is correctly excluded as a cause of secondary PPH.
Why the other options are wrong
A. Placental polyp — Placental polyps are granulation tissue or fibrin deposits at the placental implantation site that persist after delivery. They impair uterine contraction and hemostasis, causing secondary PPH typically 1–2 weeks postpartum. This is a classic cause of secondary PPH in Indian obstetric practice and requires curettage or hysterectomy if severe. B. Retained cotyledon — Retained cotyledons are remnants of placental tissue left in the uterus after incomplete placental delivery. They prevent adequate uterine contraction and cause secondary PPH, often accompanied by foul-smelling lochia and fever. Retained products are the most common cause of secondary PPH in Indian settings and require manual removal or curettage. C. Endometritis — Endometritis (infection of the endometrium) causes secondary PPH by impairing myometrial contractility and damaging the placental site, leading to defective hemostasis. It is a major cause of secondary PPH in India, especially in unhygienic deliveries or prolonged labor. Presents with fever, foul lochia, and uterine tenderness.
High-Yield Facts
- Placenta previa causes primary PPH (antepartum/intrapartum), not secondary PPH—it is resolved once the placenta is delivered.
- Secondary PPH (postpartum hemorrhage after 24 hours to 12 weeks) is caused by retained products, endometritis, placental polyps, and uterine atony—not by placental position.
- Retained cotyledons are the most common cause of secondary PPH in India; present with heavy bleeding 1–2 weeks postpartum and require manual evacuation.
- Endometritis impairs uterine contraction and hemostasis; always suspect with fever, foul lochia, and secondary PPH in unhygienic deliveries.
- Placental polyps are benign granulation tissue at the implantation site; cause secondary PPH by preventing normal involution and require curettage if symptomatic.
Mnemonics
RETAINED (Secondary PPH causes) Retained products (cotyledons) | Endometritis | Thrombin defects (coagulopathy) | Atony (uterine) | Inversion (uterine) | Neoplasia (placental polyp) | Emboli (amniotic fluid) | Dissection (placental site) Primary vs Secondary PPH Timing Primary PPH = before/during/within 24 hours of delivery (placenta previa, abruption, atony). Secondary PPH = 24 hours to 12 weeks postpartum (retained products, infection, polyps). Placenta previa is resolved once baby + placenta delivered → not a secondary cause.
NBE Trap
NBE pairs placenta previa with PPH to test whether students conflate all causes of hemorrhage. The trap is assuming any placental abnormality causes secondary PPH; in reality, placenta previa is a primary hemorrhage risk that ends after delivery, while retained products and infection persist postpartum.
Clinical Pearl
In Indian rural settings, secondary PPH from retained cotyledons is often mistaken for primary atony. The key discriminator: if bleeding starts 5–7 days postpartum with foul lochia and the uterus remains boggy despite oxytocin, suspect retained products—manual evacuation under anesthesia is the DOC, not just uterotonic drugs.
_Reference: DC Dutta's Textbook of Obstetrics (7th ed.), Ch. 24 (Postpartum Hemorrhage); Harrison's Principles of Internal Medicine, Ch. 6 (Obstetric Complications)_