Constipation is a common digestive problem that occurs during pregnancy. You may experience less frequent bowel movements, harder or drier stools, and pain or difficulty while having a bowel movement.  The number of bowel movements that a healthy person has each week can vary, so constipation symptoms may not be the same for everyone. In general, constipation is defined as having 3 or less bowel movements per week or bowel movements that are less frequent than your typical weekly routine. You can read more about constipation here.
About 11% to 38% of expecting moms experience constipation.  It is the second most common complaint by pregnant women relating to the digestive system. During pregnancy, your body experiences many changes that increase your likelihood of becoming constipated. Variations in your body’s hormones during pregnancy cause food to move more slowly through your intestines. The intestines also lose more water during pregnancy, leading to harder and drier stools. Additionally, vitamin supplements that are commonly used in pregnancy, including iron and calcium, frequently cause constipation. Your risk of becoming constipated can also increase during the later stages of pregnancy as the uterus enlarges and further slows the movement of stool through the intestines.
Expecting moms that experience constipation should first try lifestyle changes before resorting to any medications to improve their symptoms. [3,4] The following are changes that you can incorporate into your daily life to prevent constipation:
- Drink 10-12 cups of water daily. The amount of water that your body needs when you are pregnant increases. Drinking plenty of water will help prevent constipation. You can also try drinking a glass of prune juice every day.
- Be active and make mild physical activity a part of your daily routine.
- Eat a diet that includes high-fiber foods, such as vegetables, fruits, whole grain breads and cereals, bran, and prunes. It is recommended to consume 25 to 30 grams of fiber daily.
- If you are taking an iron supplement during pregnancy, you should contact your doctor about your constipation symptoms. Iron is a necessary nutrient in pregnancy, but it can also cause or worsen constipation. Your doctor may recommend changes to your iron supplementation by either reducing your dose or dividing your normal daily dose into several daily doses.
- Use the bathroom as soon as you feel the urge.
- Try drinking warm beverages when you wake up.
- Avoid foods that have very little fiber or nutritional value, such as fast food, chips, sweets, and processed foods.
If lifestyle changes have not improved your constipation, you may need to discuss a short-term treatment plan with your doctor.
Bulk-forming laxatives: Bulk-forming laxatives are usually considered the next choice if lifestyle changes did not solve the problem. These laxatives are essentially fiber-containing supplements. They make it easier for you to get extra fiber if you are having trouble getting enough through diet alone. Bulk-forming laxatives absorb water in the intestines to make stool bulkier, which encourages your intestines to push stool out. [2,5] These laxatives have been found to be safe and improve constipation symptoms when used in pregnant women, but they should be taken with plenty of water. [2,5,6] Types of bulk-forming laxatives that are available include calcium polycarbophil (FiberCon), psyllium husk (Metamucil), and methylcellulose (Citrucel). [2,5]
Osmotic Laxatives: Osmotic laxatives increase the amount of water in the intestines, which softens stool and increases the frequency of bowel movements. These medications should not be used long-term because they could cause changes in your body’s electrolyte levels. Osmotic laxatives are marketed under different names, including polyethylene glycol (Miralax), magnesium hydroxide (Milk of Magnesia), lactulose, or sorbitol.
Stool Softeners: Stool softeners work by combining water into stools to soften them and make them easier to pass. The most common stool softener available is docusate sodium (Colace). There is no evidence to support the effectiveness of stool softeners for treating constipation. 
Lubricants: Lubricants cover the surface of stool, allowing it to move more easily through the intestines. [2,5] An example of a lubricant laxative is mineral oil. It is not recommended to use mineral oil during pregnancy because it may reduce the body’s ability to absorb important vitamins.  Castor oil, another lubricant, should also not be used in pregnancy because it may result in premature contractions of the uterus. [7,8]
Stimulant Laxatives: Stimulant laxatives move stool out of the body by causing the intestines to contract. [2,5] Stimulant laxatives are marketed under different names, including senna (Senokot) and bisacodyl (Dulcolax, Correctol). Stimulant laxatives are more effective than bulk-forming laxatives for improving the symptoms of constipation, but they also cause more side effects, such as stomach pain and diarrhea.  Occasional use of these medications is considered to be safe during pregnancy, but they should only be used short-term.
Safety in Pregnancy
Many laxatives only affect the intestines and are not absorbed into the rest of the body.  For this reason, most laxatives do not increase the risk of birth defects. However, some laxatives can disrupt electrolyte balance in the body or prevent absorption of important vitamins. If laxatives are used for treatment, they should only be used for a short time until constipation symptoms improve.
Constipation is very common during pregnancy and is primarily treated through lifestyle changes, such as drinking more water, consuming a high-fiber diet, and exercising. If your constipation symptoms do not improve with these changes, your doctor may prescribe a laxative medication that can be used until your constipation symptoms clear. Over-the-counter laxatives should not be used during pregnancy without guidance from your doctor.
- S. National Library of Medicine. Constipation.
- Trottier M, Erebara A, Bozzo P. Treating Constipation During Pregnancy.
- Tobah, Yvonne. Pregnancy week by week.
- American Pregnancy Association. Pregnancy and Constipation.
- S. Department of Health and Human Services. Treatment for Constipation.
- Rungsiprakarn P, Laopaiboon M, Sangkomkamhang US, et al. Interventions for treating constipation in pregnancy.
- American College of Gastroenterology. Pregnancy in Gastrointestinal Disorders.
- Servey J, Chang J. Over-the-counter medications in pregnancy.