Which non-circulatory physiologic change occurs during pregnancy?

• A. The GI tract smooth muscle relaxes.
• B. The GI tract becomes more active and empties faster.
• C. Stomach empties more quickly.
• D. The kidneys increase in size and volume.

Answer: (A)

During pregnancy, hormonal changes—especially higher progesterone—cause smooth muscle relaxation throughout the GI tract. This reduces GI motility and slows gastric emptying, a non-circulatory change because it involves the function of the digestive system rather than the heart or blood vessels. That’s why the option describing GI smooth muscle relaxation best fits: it explains a functional, non-circulatory adaptation to pregnancy and aligns with common pregnancy-related GI symptoms like constipation and reflux. The other statements describe increased GI activity or faster emptying, which progesterone does not cause. (Renal enlargement is another pregnancy adaptation, but the GI motility change is the characteristic non-circulatory physiologic change highlighted here.)