Constipation during pregnancy

Written by Jessica McKinney, PT, MS and Samantha Pulliam, MD and sponsored by

Things moving a little slower than normal? You may be among the 40% of women who experience pregnancy-related constipation. So what causes these digestive changes, and what can you expect throughout pregnancy and early postpartum?

During the first and second trimesters, the main reason for digestive problems is related to the hormone progesterone. During pregnancy, progesterone causes relaxation of the smooth muscles in the body (all the muscles we don’t have voluntary control over, like the muscles lining our digestive tract). This is important during pregnancy because it keeps you from having contractions too early in the pregnancy, but it can also slow down the motion of digestion, the involuntary action within our gut that moves things along, leading to constipation.

Progesterone also relaxes the sphincter muscle between the esophagus (the tube that carries food from the mouth) and the stomach. This relaxation, coupled with slower gastric (stomach) emptying, is the reason you may also be experiencing gastric reflux or heartburn. Women who experience symptoms of nausea and heartburn may take anti-nausea medications and/or limit water and fiber intake to try to improve those symptoms, but both nausea medications and limiting fiber and fluids can also contribute to constipation.

Some research shows that constipation may decrease as pregnancy progresses into the third trimester. The jury is still out here. It may be that women have learned to better manage constipation with diet and exercise by that time. But still, some women may continue to experience constipation or have new onset constipation during the third trimester. This is thought to be due to the increased pressure of the growing uterus on the pelvic floor, which may obstruct (block) stool during a bowel movement.

The good news is that constipation can be managed fairly well with diet and exercise. It’s important to drink lots of water and eat fiber-rich foods, such as fruits, vegetables, and whole grains. You may also want to discuss with your health care provider options for fiber supplements or stool softeners that are safe for pregnancy. And if you are taking iron supplements, these can also contribute to constipation, but there may be alternatives that are gentler on your gut. Fortunately, for most women, things eventually return to normal, though it may take some vigilance and time. By 12 months postpartum, complaints of constipation drop significantly compared to pregnancy and the early postpartum.

About the authors:
Ms. McKinney is a physical therapist and has specialized in pelvic and women’s health throughout her career. Her background includes women’s health education, advocacy, and business and program development in the US as well as in low-resource global health settings. She currently serves as Vice President of Medical Affairs and Clinical Advocacy at Renovia Inc. 

Dr. Pulliam a fellowship-trained and board certified urogynecologist, a subspecialty of medicine focused exclusively on female pelvic health. She has been in clinical and leadership positions at Massachusetts General Hospital and the University of North Carolina (Chapel Hill), as well as within the American Urogynecologic Society, and she currently serves as the Chief Medical Officer at Renovia Inc. 


Shin GH, Toto EL, Schey R. Pregnancy and Postpartum Bowel Changes : Constipation and Fecal Incontinence. Am J Gastroenterol. 2015;110(4):521-529. doi:10.1038/ajg.2015.76.

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