What causes constipation in pregnancy?

• A. Increased intestinal motility
• B. Progesterone relaxes the GI tract and decreases motility
• C. High fiber intake
• D. Exercise increases

Answer: (B)

During pregnancy, rising progesterone relaxes smooth muscle throughout the body, including the gastrointestinal tract. This slows peristalsis, increases transit time, and leads to more water reabsorption from stool, resulting in constipation. So the cause is the progesterone-induced relaxation of the GI tract and decreased motility. Increased motility would cause diarrhea, and high fiber intake or exercise help prevent constipation rather than cause it.