In a 34-week gestation patient with syncope, pallor, lethargy, no radial pulses, and heavy bright red vaginal bleeding with a low hemoglobin, which obstetric emergency is most likely?

• A. Placenta previa
• B. Placental abruption
• C. Spontaneous abortion
• D. Uterine rupture

Answer: (A)

Painless, heavy vaginal bleeding in the third trimester with signs of maternal hypovolemia points most strongly to placenta previa. When the placenta sits low and covers the cervical os, bleeding can occur without uterine contractions or significant abdominal pain, and it can be brisk enough to cause syncope, pallor, lethargy, and a reduced or absent radial pulse as blood loss accumulates. This pattern fits placenta previa well.

Placental abruption, by contrast, usually presents with painful vaginal bleeding and a tender, often rigid uterus, along with frequent contractions and fetal distress. Spontaneous abortion is unlikely at 34 weeks, since abortion refers to pregnancy loss earlier in gestation. Uterine rupture typically presents with sudden severe abdominal pain, rapid maternal/fetal deterioration, and is often linked to a prior uterine scar.

Thus the scenario aligns best with placenta previa.