A 32-year-old G3P2 woman at 28 weeks gestation presents with painless bright-red vaginal bleeding. Transabdominal ultrasound is inconclusive; transvaginal ultrasound confirms the structure marked **A** in the diagram completely covers the internal cervical os. She has a history of two prior cesarean deliveries. Which of the following is the MOST appropriate next step in management?

Explanation

## Why option B is correct The structure marked **A** — placenta covering the internal cervical os — defines placenta previa. The clinical anchor mandates that placenta previa requires **scheduled cesarean delivery at 36–37 weeks** (or 34–35 weeks if placenta accreta spectrum is suspected). At 28 weeks, the patient is preterm; antenatal corticosteroids are indicated for fetal lung maturity. Critically, with **two prior cesarean deliveries**, the risk of placenta accreta spectrum rises substantially (~3% per prior CS, cumulative ~6–9% with 2 prior CS). Screening for accreta (loss of placental–myometrial interface, lacunae, disrupted bladder line, Doppler hypervascularity) is mandatory. Pelvic rest (no intercourse, no digital exams) is the standard of care to prevent hemorrhage. This option correctly integrates the anchor (placenta covering internal os), the clinical presentation (painless bleeding), the gestational age (preterm → corticosteroids), and the critical risk factor (prior cesarean → accreta screening). ## Why each distractor is wrong - **Option A**: Digital cervical examination is **absolutely contraindicated** in placenta previa — it can precipitate catastrophic hemorrhage. The clinical anchor explicitly states "NEVER PERFORM DIGITAL VAGINAL EXAM in suspected previa." This is a high-stakes safety rule. - **Option C**: Immediate cesarean at 28 weeks without corticosteroids contradicts standard management. Placental migration does occur before 32 weeks (though less likely with scarring), but the anchor mandates scheduled delivery at 36–37 weeks in asymptomatic or stable patients. Denying corticosteroids at 28 weeks increases neonatal morbidity and mortality unnecessarily. - **Option D**: Vaginal delivery is contraindicated in placenta previa — the placenta covers the birth canal. The anchor states "CESAREAN DELIVERY for ALL placenta previa." Painless bleeding does not change this absolute indication. **High-Yield:** Placenta previa = painless 3rd-trimester bleeding + placenta covering internal os → scheduled cesarean at 36–37 weeks; NEVER digital exam; prior cesarean → screen for accreta. [cite: Williams Obstetrics 26e Ch 41; Rumack Diagnostic Ultrasound 5e]