Okay, let's tackle this question. The patient is a 21-year-old primigravida at 39 weeks with painless antepartum hemorrhage. The key points here are painless bleeding and the exam findings: soft, non-tender uterus with the head engaged.

First, I need to recall the common causes of antepartum hemorrhage. The two main ones are placenta previa and abruption placentae. But abruption is usually associated with abdominal pain and a tender uterus, so that might not fit here. Placenta previa, on the other hand, typically presents with painless bleeding, especially in the third trimester. The exam findings support this since the uterus is soft and non-tender, and the head is engaged, which might suggest a low-lying placenta.

The management for placenta previa depends on the severity and gestational age. Since she's at 39 weeks, which is term, the standard approach is often cesarean delivery. Vaginal delivery is contraindicated if the placenta is covering the cervix. So if the bleeding is significant and she's at term, the next step would be to prepare for a cesarean. But wait, the options aren't listed here. The correct answer in this case would likely be a cesarean section.

Now, looking at the options (even though they're not provided), the incorrect options might include things like induction of labor or vaginal delivery, which are not appropriate for placenta previa. Other options could be unnecessary interventions like bed rest or monitoring without delivery, which aren't suitable if the placenta is previa and the patient is at term with active bleeding.

The clinical pearl here is that placenta previa is a leading cause of painless third-trimester bleeding, and management is based on gestational age and placental location. At term, cesarean delivery is the standard.

**Core Concept**
Painless antepartum hemorrhage in the third trimester is most commonly caused by **placenta previa**, a condition where the placenta implants over the internal cervical os. Management depends on gestational age, bleeding severity, and fetal status.

**Why the Correct Answer is Right**
At 39 weeks, with painless bleeding and a non-tender uterus, **placenta previa** is the likely diagnosis. The head is engaged, suggesting a low-lying placenta. Definitive management in this scenario is **cesarean delivery** to prevent life-threatening hemorrhage during vaginal delivery. Immediate surgical delivery is indicated for complete placenta previa at term.

**Why Each Wrong Option is Incorrect**
**Option A:** Induction of labor is contraindicated in placenta previa due to high risk of severe hemorrhage.
**Option B:** Vaginal delivery is unsafe if placenta previa is confirmed.
**Option C:** Expectant management (e.g., bed rest) is only considered for stable patients with marginal previa and no active bleeding.

**Clinical Pearl / High-Yield Fact**
Placenta previa is a **classic exam trap**: "painless, painless, painless"—remember it causes **painless third-trimester bleeding**. Always confirm placental location via ultrasound before labor.

**Correct Answer: C. Cesare

✓ Correct Answer: C. Pelvic examination in OT