Prolapse of the umbilical cord primarily threatens the fetus by causing which complication?

• A. Maternal hypertension.
• B. Fetal hypoxia due to the cord lying below the presenting part.
• C. Placental abruption.
• D. Uterine rupture.

Answer: (B)

The key idea is that a prolapsed umbilical cord threatens the fetus primarily through compression of the cord, which cuts off blood flow and oxygen delivery. When the cord slides ahead of the presenting part into the birth canal, it can be squeezed between the presenting part and the vaginal walls. This compression reduces the flow of oxygen-rich blood to the fetus, leading to fetal hypoxia and distress. While maternal hypertension, placental abruption, and uterine rupture are serious obstetric problems, they are not the direct mechanism by which cord prolapse endangers the fetus. Signs on monitoring often show fetal distress due to hypoxia, and the priority is to relieve cord compression and expedite delivery.