Constipation is defined as having bowel movements fewer than three times per week. The stools are typically hard, dry, small in size, and difficult to eliminate. Constipation may be accompanied by straining, pain, bloating, cramping, and the sensation of a full bowel. It is a bothersome common complaint of pregnancy, particularly in the second and third trimesters. Women who are habitually constipated may become more so during pregnancy. The prevalence of constipation in pregnancy is reported to be 11% to 38%. It has been generally accepted that decreased gastric motility in pregnancy is a result of increased circulating progesterone levels. More recent experimental evidence suggests that elevated estrogen concentrations are involved in delayed motility through an enhancement of nitric oxide release. Slow transit time of food through the intestinal tract leads to increased water absorption and thereby to constipation. Dietary factors, particularly inadequate fiber intake and lack of exercise, contribute to constipation, as does increased pressure of the growing uterus on the rectum as pregnancy becomes advanced. Ignoring the urge to have a bowel movement can also contribute to the problem. Iron-deficiency anemia can contribute to constipation, as can elemental iron supplements.
Constipation first presenting in pregnancy does not require an extensive evaluation, and is considered a normal pregnancy complaint. Constipation accompanied by other symptoms, for example, blood in the stools, or unresponsive to treatments requires further investigation to rule out possible pathology.
Conventional Treatment Of Constipation
Most patients respond to simple dietary and lifestyle measures. Treatment during pregnancy is similar to that for the general population; however, special care must be taken to avoid medications that may be harmful to the fetus or disrupt the pregnancy.
The first line of treatments for constipation include:
• Increasing water consumption to eight glasses per day: Avoiding dehydration will keep the stools softer and make them easier to pass; liquids that contain caffeine (coffee, tea, cola) increase dehydration.
• Increasing dietary fiber to 20 to 35 g / day: High-fiber foods increase stool bulk and facilitate bowel evacuation; high-fiber food sources include fruits, vegetables, whole grains and bran cereals, and beans.
• Minimizing consumption of constipating food items, for example, ice cream, meats, cheese, and high-fat foods can increase constipation, especially in a low-fiber diet.
• Increasing daily activity: Even increased daily walking, as well as other forms of exercise, for unknown reasons, will prevent constipation.
• Encouraging use of the bathroom as soon as there is the urge to eliminate; putting off the need to have a bowel movement can actually blunt the sensation over time, leading to constipation.
• Trying to have a bowel movement at a regular time each day by sitting on the toilet and trying to relax each morning shortly after awakening. Some women, particularly in advanced pregnancy, find that putting their feet up on a stool while sitting on the toilet relieves pressure of the uterus on the lower intestines, facilitating a bowel movement.
Fiber Supplementation: Bulk-Forming Laxatives
Fiber supplements, which are bulk-forming laxatives, are effective, safe, and without side effects when used in appropriate doses; however, limited studies are available on the use of laxatives in pregnancy. In addition to softening the stool by keeping more fluid in the bowel lumen, the presence of the increased bulk is thought to stimulate intestinal peristalsis. Examples include wheat fiber (e.g., wheat bran), psyllium, flax seed, and pectin, to 25 g per day. Laxative effects may take 3 to 7 days to be noticeable. If side effects occur, switching to a different bulk laxative may help. Taken in excessive qualities they can lead to cramping, gas, diarrhea, and bloating. Bulk laxatives have a pregnancy B category (Table FDA Categories for Drug Use during Pregnancy). Stool softeners are not recommended for use during pregnancy.
Treatment Summary for Constipation
• Increase fluid intake, especially water and noncaffeinated beverages.
• Increase consumption of high-fiber foods such as fruits, vegetables, whole grains, and beans.
• Decrease consumption of constipating foods, particularly those high in fat, such as cheese, milk, and ice cream.
• Increase exercise, even a brisk walk once daily.
• Do not ignore or delay the urge to have a bowel movement — when you’ve got to go, you’ve got to go!
• HERBS ARE NOT A SUBSTITUTE FOR DIETARY AND LIFESTYLE CHANGES!
FDA Categories for Drug Use during Pregnancy
|A||Adequate, well-controlled studies in pregnant women have not shown an increased risk of fetal abnormalities.|
|B||Animal studies have revealed no evidence of harm to the fetus; however, there are no adequate and well-controlled studies in pregnant women OR
Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus.
|C||Animal studies have shown an adverse effect and there are no adequate and well-controlled studies in pregnant women OR No animal studies have been conducted and there are no adequate and well-controlled studies in pregnant women.|
|D||Studies, adequate well-controlled or observational, in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy may outweigh the potential risk.|
|X||Studies, adequate well-controlled or observational, in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. The use of the product is contraindicated in women who are or may become pregnant.|
Osmotic laxatives are indigestible sugars that work by increasing the amount of fluid that is retained in the bowel. Sorbitol, lactulose, and glycerin appear to be safe sources for use during pregnancy. Saline, phosphorus, and magnesium salt laxatives, including many prepackaged enemas, are not advisable during pregnancy because they can cause salt retention in the mother.
Stimulant laxatives are best used in pregnancy only after other measures have failed to relieve constipation. Examples of stimulant laxatives include senna, cascara sagrada, and aloes. Of these, only senna is considered safe (see senna discussion in the following) for use during pregnancy. Approved as an over-the-counter (OTC) medication, senna is an herb and is thus discussed in the following section with other botanicals. Stimulants are more likely to cause side effects of diarrhea and abdominal pain than are bulk laxatives.
Case History 1
Sara, a nurse, was pregnant with her second baby. Her husband, Jeff, is a physician. In addition to these pregnancies, Sara had experienced two miscarriages, one prior to her first live birth, and the second between the two pregnancies. At 10 weeks gestation, Sara was experiencing moderate constipation, so she decided to go to the local health food store and try a natural laxative. She purchased a pre-packaged mix containing a number of herbs including senna, cascara sagrada, and buckthorn. Concerned about the safety of these herbs she called her obstetrician for information. He told her that herbs do not do anything, and that it was fine to take them. Sara took the herbs for 5 days, after which time she began having cramping and spotting. She miscarried 3 days later. Although the miscarriage may have been entirely unrelated to the use of these herbs, this case illustrates a serious lack of knowledge on the part of the obstetrician and the need for medical education to include training at least in the herbs contraindicated in various circumstances, for example, pregnancy.