North American Registry of Midwives (NARM) Practice Exam

During labor, the upper zone of the uterus, commonly referred to as the fundus, undergoes specific changes that are essential for effective contraction and progression of labor. The correct response indicates that the upper zone shortens and thickens.

As labor progresses, the muscles of the uterine wall contract in a coordinated manner to facilitate the descent of the fetus. This action leads to the upper segment of the uterus becoming more contracted, which is characterized by a shortening of the length of this segment due to the strong contractions of the myometrium. Simultaneously, as the muscle fibers contract tightly, the area also thickens, which helps in exerting more pressure on the fetus, aiding in its descent through the birth canal.

This mechanism is crucial for ensuring a strong and efficient labor process, as a properly functioning upper zone helps to push the fetus down toward the cervix. Understanding this physiological change is important for midwives when monitoring labor progress and ensuring the well-being of both the mother and the infant.