Which condition occurs when the placenta partially or fully blocks the cervical opening in the second or third trimester?

• A. Placenta previa
• B. Placenta abruption
• C. Rh incompatibility
• D. Preeclampsia

Answer: (A)

Placenta previa is when the placenta implants low in the uterus, covering the cervix either partially or completely. Because the cervix opens during the second and third trimesters in preparation for birth, a placenta that sits near or over the cervical opening can block it, which is exactly what the question describes. This condition often causes vaginal bleeding that is painless, and it may require special care or delivery by cesarean section if the placenta remains over the cervix as pregnancy progresses.

In contrast, placenta abruption involves the placenta peeling away from the uterine wall and typically presents with painful vaginal bleeding and uterine contractions. Rh incompatibility is about the mother’s immune system reacting to fetal red blood cells, not the placenta’s position. Preeclampsia involves high blood pressure and signs of organ strain, not cervical obstruction.