Constipation in Pregnancy

Constipation is yet another uncomfortable symptom that is very common in pregnancy.

We can blame our hormones for this one too.  Progesterone circulates at an all time high during pregnancy and plays a major role in bloating and constipation.  

How do hormones cause constipation?

Progesterone slows down the motility of the intestines.  This means it takes longer for your food to be digested and then passed as a bowel movement.  

Progesterone can also reduce the levels of another hormone called motilin.  Motilin is responsible for regulating the movements of the digestive tract.  Low levels of this hormone may make you more constipated. 

Other reasons you may be constipated during pregnancy

As your pregnancy progresses, your uterus can put pressure on the colon making it more difficult to have a bowel movement.  

Prenatal vitamins contain iron.  Iron supplements are a known cause of constipation in both pregnant and non-pregnant people. 

Occasionally, some women end up on bed-rest during their pregnancy.  Decreased physical activity is known to contribute to constipation.

Management of constipation in pregnancy

I typically recommend diet and lifestyle changes first for all patients complaining of constipation, whether they are pregnant or not. Simple changes can include:

• Increasing fluid intake to more than 8 glasses of water per day
• Increase fiber consumption to 20-35g fiber per day
• Increase light physical activity if your physician advises it is safe to do so

Sometimes over-the-counter medications are required to help manage constipation.  The most common products I recommend are bulk-forming laxatives that contain psyllium or an osmotic laxative called PEG 3350.  These medications are not absorbed into the body and can be used safely for long durations. They may take several days to start working and have minimal side effects like gas and bloating.

Stimulant laxatives like sennosides or bisacodyl are also available over-the-counter.  These medications are not absorbed into the body, but have a much higher risk of side effects like cramping and diarrhea.  I don’t recommend trying these ones first. 

Laxatives that should not be used during pregnancy include mineral oil and castor oil.  Mineral oil may decrease absorption of important vitamins in the diet.  Castor oil may cause premature uterine contractions.  Stool softeners like docusate are ineffective laxatives.

Constipation is an uncomfortable, but manageable symptom during pregnancy

While being constipated can be frustrating during your pregnancy, it is manageable and should go away soon after you deliver your baby.  I always recommend diet and lifestyle changes before the use of laxatives.  If these changes are not working for you, talk to your health care provider.

This post was co-authored by Erin Manchuk, BScPharm, BCGP and Stephanie Liu, MD, MSc, CCFP, BHSc.

References:

Christofides ND, Ghatei MA, Bloom SR, Borberg C, Gillmer MD. Decreased plasma motilin concentrations in pregnancy.  Br Med J (Clin Res Ed). 1982; 285(6365):1453-4.

Bradley CS¹, Kennedy CM, Turcea AM, Rao SS, Nygaard IE. Constipation in pregnancy; prevalence, symptoms, and risk factors.  Obstet Gynecol. 2007;110(6):1351-7.

Trottier M¹, Erebara A, Bozzo P. Treating constipation during pregnancy.  Can Fam Physician. 2012;58(8):836-8.  

Rungsiprakarn P¹, Laopaiboon M, Sangkomkamhang US, Lumbiganon P, Pratt JJ. Interventions for treating constipation in pregnancy.  Cochrane Database Syst Rev. 2015 Sept 4;(9):CD011448

Shin GH¹, Toto EL¹, Schey R¹. Pregnancy and postpartum bowel changes: constipation and fecal incontinence.  Am J Gastroenterol. 2015;110(4)521-9.  

Body C¹, Christie JA².  Gastrointestinal Diseases in Pregnancy: Nausea, Vomiting, Hyperemsis Gravidarum, Gastroesophageal Reflux Disease, Constipation, and Diarrhea. Gastroenterol Clin North Am. 2016 Jun;45(2):267-83.  

http://s3.gi.org/physicians/PregnancyMonograph.pdf(Accessed 19 July 2019)