GASTROINTESTINAL
Stomach: Gastric motility decreases and emptying time increases from the
progesterone effect on smooth muscle. This increase in stomach residual
volume, along with upward displacement of intraabdominal contents by the
gravid uterus, predisposes to aspiration pneumonia with general anesthesia at
delivery.
Large bowel: Colonic motility decreases and transit time increases from the
progesterone effect on smooth muscle. This predisposes to increased colonic
fluid absorption, resulting in constipation.