Which cephalic presentation is most likely to require a cesarean delivery?

The brow presentation occurs when the fetal head is extended such that the forehead is oriented toward the birth canal. In this position, the biparietal diameter of the fetal head is presenting first, which can create a wider diameter than in a normal vertex presentation (occiput). This can complicate the labor process, potentially leading to dystocia, or prolonged labor due to mechanical obstruction. The brow presentation may not allow sufficient flexion of the neck, making vaginal delivery difficult, which is why a cesarean delivery is often indicated in these cases to ensure the safety of both the mother and the fetus.

In contrast, the other options generally have better prospects for vaginal delivery: the face presentation often allows delivery due to the fetal head being adequately positioned for descent; the occiput presentation is the ideal vertex position for birth; and the shoulder presentation can lead to the need for a cesarean delivery as well, but is classified separately and is treated distinctly in obstetric management due to its clear identification as a transverse lie.