A 27-year-old woman in her 2nd trimester of pregnancy comes to the office due to constipation. Her stools have become increasingly hard and pellet-like over the past few weeks; bowel movements before then were always regular. She also has mild crampy abdominal pain and bloating, both of which improve after defecation. Medical history and family history are both unremarkable. This is the patient's first pregnancy and has so far been uncomplicated. On physical examination, the abdomen appears gravid but nontender. Which of the following best explains this patient's symptoms?

Question

A 27-year-old woman in her 2nd trimester of pregnancy comes to the office due to constipation.  Her stools have become increasingly hard and pellet-like over the past few weeks; bowel movements before then were always regular.  She also has mild crampy abdominal pain and bloating, both of which improve after defecation.  Medical history and family history are both unremarkable.  This is the patient's first pregnancy and has so far been uncomplicated.  On physical examination, the abdomen appears gravid but nontender.  Which of the following best explains this patient's symptoms?

Quizplus · Accepted Answer

11ec160b_3cc2_7216_9249_bdf9b5d6a431_MD0001_00 Pregnancy has multiple effects in the gastrointestinal tract due to increasing levels of progesterone and estrogen as well as the effects of a gravid uterus on surrounding structures. Constipation is particularly common in pregnant patients and is largely due to the effects of progesterone, which has been shown to reduce colonic smooth muscle activity. Progesterone also prevents the release of motilin, a hormone responsible for stimulating the fasting migrating myoelectric complex, which normally helps propel undigested food from the small intestines into the colon. Constipation may be exacerbated in later stages of pregnancy as the gravid uterus increases pressure on the small intestine, slowing intestinal transit. Other common gastrointestinal alterations in pregnancy include reduced lower esophageal sphincter pressure (promoting gastroesophageal reflux) and gallbladder stasis (increasing the likelihood of developing gallstones). Hemorrhoids are also common and result from a rise in pressure within the rectal venous system due to the gravid uterus. (Choice B) The parasympathetic nervous system stimulates peristalsis and gastrointestinal motility. Reduced parasympathetic input to the colon can lead to constipation; however, this typically occurs with neurologic disorders (eg, spinal cord injury, multiple sclerosis). (Choice C) Defecatory dysfunction results from an inability to relax pelvic floor muscles, which prevents proper evacuation of stool from the rectal vault. Although this can occur after trauma (eg, traumatic vaginal delivery), it is not a physiologic change that occurs during pregnancy. (Choice D) Thickened intestinal secretions can cause constipation; however, this is typically seen in patients with cystic fibrosis, which affects water and electrolyte transportation. Patients with cystic fibrosis are typically diagnosed in infancy and have recurrent respiratory infections and failure to thrive. (Choice E) Rectoceles occur when the rectum herniates into the vaginal canal through a thinned rectovaginal septum. Although they also cause constipation, rectoceles typically occur in elderly individuals with a history of multiple vaginal deliveries, not during pregnancy. Patients often report needing to manually compress the vagina to induce bowel movements. Educational objective: Constipation is common during pregnancy and results from the inhibitory effect of progesterone on colonic smooth muscle contractions and the fasting migrating myoelectric complex. Other common pregnancy-related changes of the gastrointestinal system include decreased lower esophageal sphincter pressure (leading to gastroesophageal reflux) and gallbladder stasis (leading to gallstone formation).

A 27-Year-Old Woman in Her 2nd Trimester of Pregnancy Comes