A G2P3 at 38 weeks with complete placenta previa diagnosed at 18 weeks presents with contractions and large amounts of bright red vaginal bleeding. The fetal heart rate baseline is 100/min with variability and late decelerations. What is the most likely diagnosis?

• A. Placenta previa
• B. Separation of the placenta
• C. Uterine rupture
• D. Fetal distress without placental complication

Answer: (B)

Contractions with heavy, bright red bleeding in the third trimester, plus a fetal heart tracing showing late decelerations, point to placental separation (placental abruption). Late decelerations reflect fetal hypoxia from reduced placental perfusion, which is a hallmark of abruption. The uterus is typically tense and painful with placental separation, and bleeding can be brisk.

Placenta previa, by contrast, usually presents with painless vaginal bleeding because the placenta lies over the cervical os and bleeding is not driven by contractions or placental perfusion problems in the same way. Uterine rupture would present with sudden severe abdominal pain, a typically rigid or hypertonic uterus, and rapid fetal deterioration—not just bleeding with late decelerations. Fetal distress without placental complication wouldn’t account for the vaginal bleeding and the contractions observed.