A Pharmacist’s Guide to Managing Constipation in Pregnancy

This article was sponsored by Bayer, maker of MiraLAX^® (PEG 3350).

Prevalence of Constipation During Pregnancy

Constipation occurs when the waste material in the lower digestive tract hardens, making it difficult to pass stool.¹ Symptoms of constipation can include having fewer than 3 bowel movements a week; hard, dry, or lumpy stools; and pain or straining when passing stools.² With an estimated 41 million adults suffering from constipation in the US each year,³ it is a common condition that many people experience at some point, and it can become even more prevalent with certain risk factors such as pregnancy.¹

Studies show that women are more likely than men to experience constipation.⁴ One literature review included 16 studies that had population-based samples of adults with constipation and reported results on prevalence, natural history, gender, and age.⁴ This review observed that female-to-male constipation ratios range from 1.01 to 3.77 with a median of 2.0.⁴ Various factors may cause constipation, such as diet, iron supplementation, hormone fluctuation, pregnancy, and menopause.³

A review of existing studies done by the Cochrane Library in 2015 found that constipation affected approximately 11% to 38% of pregnant women, with symptoms being most prevalent during the second and third trimesters.⁵ This study evaluated the effectiveness of different treatments for constipation in pregnant women. It was a systematic review of controlled trials, assessing interventions intended to improve defecation frequency and ease. Researchers conducted electronic searches, evaluating trials for methodological quality and extracting data independently. Two small trials met the inclusion criteria: one examined fiber supplements, and the other compared stimulant and bulk-forming laxatives. Results indicated that fiber supplements significantly improved defecation frequency and stool consistency, while stimulant laxatives were more effective than bulk-forming laxatives but caused more adverse events such as diarrhea and abdominal pain. Challenges included small sample sizes, lack of placebo controls, and limited long-term acceptability data. Further research is needed to compare the effectiveness and patient preference for different treatment options including dietary modifications and exercise.⁵ Various factors such as hormonal changes, reduced physical activity, and diet are identified as key contributors to constipation during pregnancy.¹

Causes and Risks of Pregnancy-Related Constipation

Constipation can develop at any point during pregnancy, typically as hormone levels rise to support the pregnancy.¹ Although many women experience constipation throughout pregnancy, it can be more prevalent in the third trimester, when the weight of the fetus may exert pressure on the bowel.¹ Increased progesterone levels during pregnancy are a primary factor contributing to constipation, as progesterone relaxes the muscles of the bowel, slowing stool passage.¹ This slowdown allows for greater absorption of nutrients and water, but it also results in drier stool, making it more difficult to pass.¹ Additional factors that may contribute to constipation during pregnancy include reduced physical activity and the use of iron supplements, which are commonly found in prenatal vitamins.¹

Chronic constipation can result in long-term complications. If left untreated, it may lead to serious health issues including hemorrhoids, anal fissures, rectal prolapse, or fecal impaction.² Constipation is also linked to a diminished quality of life due to factors such as physical discomfort, negative body image, and potential psychological effects like frustration and low mood.⁶ People experiencing constipation are more likely to report poor overall health, reduced physical functioning, decreased energy levels, and challenges in social interactions.⁶

OTC Treatment Recommendations

There are several nonpharmacological and pharmacological options intended to relieve constipation in pregnant women. The American Pregnancy Association recommends that pregnant patients consume 25 to 30 grams of fiber daily, drink 10 to 12 cups of water, and engage in 20 to 30 minutes of moderate exercise, such as walking or swimming, 3 times a week to help manage constipation.⁷ If these lifestyle changes don’t provide relief, patients should consult with their health care provider before using laxatives or fiber supplements, as not all treatments are safe during pregnancy.¹

Over-the-counter (OTC) laxatives employ various mechanisms of action, providing several options for managing occasional constipation during pregnancy. Some of these treatments include osmotic laxatives, psyllium fibers, stool softeners, and stimulant laxatives (Table).^3,8-11

The American College of Obstetricians and Gynecologists and the American Gastroenterological Association recommend polyethylene glycol as the preferred treatment for constipation in pregnant women and consider osmotic laxatives to be low risk.^12,13 Short-term use of docusate, senna, and bisacodyl is considered safe, whereas magnesium citrate, sodium phosphate, castor oil, and mineral oil are not considered safe and should be avoided.¹³

Role of the Pharmacist

Pharmacists play a vital role in counseling pregnant patients on the safe use of OTC medications for occasional constipation. These responsibilities include assisting with the selection of appropriate, evidence-based treatments that are safe for use during pregnancy. Providing clear instructions on proper dosing and administration while educating patients about potential adverse events is essential. Additionally, pharmacists have a responsibility to emphasize the importance of consulting with a health care provider before initiating any treatment, ensuring alignment with prenatal care plans and safeguarding maternal and fetal health.

Conclusion

Constipation is a common and burdensome condition for many pregnant women, significantly impacting their quality of life.¹ Following professional guidelines can aid in safe and effective management of constipation, helping to alleviate symptoms while prioritizing maternal and fetal health.

Evidence supports the safety and efficacy of certain laxatives when used appropriately during pregnancy.¹⁴ However, the importance of individualized advice from a health care professional cannot be overstated. Tailored recommendations consider the unique needs and medical history of each patient, ensuring that any treatment aligns with overall prenatal care for optimal outcomes.

REFERENCES

1. Pregnancy constipation. Cleveland Clinic. Reviewed October 19, 2021. Accessed January 28, 2025. https://my.clevelandclinic.org/health/diseases/21895-pregnancy-constipation
2. Constipation. Mayo Clinic. October 20, 2023. Accessed January 28, 2025. https://www.mayoclinic.org/diseases-conditions/constipation/symptoms-causes/syc-20354253
3. About constipation. MiraLAX. Accessed January 28, 2025. https://www.MiraLAX.com/healthcare-professionals/about-constipation#otc
4. McCrea GL, Miaskowski C, Stotts NA, Macera L, Varma MG. A review of the literature on gender and age differences in the prevalence and characteristics of constipation in North America. J Pain Symptom Manage. 2009;37(4):737-745. doi:10.1016/j.jpainsymman.2008.04.016
5. Jewell DJ, Young G. Interventions for treating constipation in pregnancy. Cochrane Database Syst Rev. 2000;2001(2):CD001142. doi:10.1002/14651858.CD001142
6. Rungsiprakarn P, Laopaiboon M, Sangkomkamhang US, Lumbiganon P, Pratt JJ. Interventions for treating constipation in pregnancy. Cochrane Database Syst Rev. 2015;2015(9):CD011448. doi:10.1002/14651858.CD011448.pub2
7. Constipation during pregnancy. American Pregnancy Association. Accessed January 30, 2025. https://americanpregnancy.org/healthy-pregnancy/pregnancy-health-wellness/constipation-during-pregnancy/
8. Hammer HF, Santa Ana CA, Schiller LR, Fordtran JS. Studies of osmotic diarrhea induced in normal subjects by ingestion of polyethylene glycol and lactulose. J Clin Invest. 1989;84(4):1056-1062. doi:10.1172/JCI114267
9. Andrews CN, Storr M. The pathophysiology of chronic constipation. Can J Gastroenterol. 2011;25(suppl B):16B-21B.
10. DiPalma JA, DeRidder PH, Orlando RC, et al. A randomized, placebo-controlled, multicenter study of the safety and efficacy of a new polyethylene glycol laxative. Am J Gastroenterol. 2000;95(2):446-450. doi:10.1111/j.1572-0241.2000.01765.x
11. Fiorini K, Sato S, Schlachta CM, Alkhamesi NA. A comparative review of common laxatives in the treatment of constipation. Minerva Chir. 2017;72(3):265-273. doi:10.23736/S0026-4733.17.07236-4
12. Ray J, LaBundy, J. Lower gastrointestinal tract disorders. American College of Obstetricians and Gynecologists. June 2022. Accessed January 28, 2025. https://www.acog.org/clinical/journals-and-publications/clinical-updates/2022/06/lower-gastrointestinal-tract-disorders
13. Mahadevan U, Kane S. American gastroenterological association institute medical position statement on the use of gastrointestinal medications in pregnancy. Gastroenterology. 2006;131(1):278-282. doi:10.1053/j.gastro.2006.04.048
14. Gomes CF, Sousa M, Lourenço I, Martins D, Torres J. Gastrointestinal diseases during pregnancy: what does the gastroenterologist need to know? Ann Gastroenterol. 2018;31(4):385-394. doi:10.20524/aog.2018.0264