Constipation is second only to nausea as the most common gastrointestinal complaint in pregnancy. It is currently estimated that up to 40% of pregnant women experience constipation and its related symptoms, which can occur during any trimester.
Women should note that constipation can occur even with frequent bowel movements; however, these bowel movements can be uncomfortable, dry, and hard, and lead to straining. Conversely, infrequent bowel movements do not necessarily indicate constipation, as this can be normal for some women.
However, even though commonly cited, evidence is inconsistent regarding GI tract motility during pregnancy, and rate of emptying has only been partially studied. Part of this inconsistency is due to the limited methods researchers can use to measure emptying time, as the most accurate imaging techniques use radiation.
Elevated levels of progesterone and relaxin are assessed to work together to cause food to move slower through the digestive system. Even if motility is debated, any slight effect on motility can increase water absorption in the colon, leading to dry and hard stool that is difficult to pass.
“Mechanical” problems as pregnancy progresses can compound constipation symptoms. As the uterus expands, it can impede movement of fecal matter through the colon. Further, women can have a more difficult time exerting the pressure necessary to have a bowel movement.
Iron supplements are commonly associated with constipation, the frequency and severity of which depends on the amount of iron released in the stomach. Pregnant women taking iron supplements should consult their HCP if their constipation becomes too unbearable, as there are different options available.
Constipation can also cause hemorrhoids (usually painless), which occur due to straining while trying to pass a bowel movement; anal fissures can also develop (painful tears or small cuts in the skin around the anus). When either occur, women may see bright red blood either in the toilet or when cleaning. If the blood is a darker color, such as dark red or black, it could be caused from other conditions and women should call their HCP.
In some cases, severe constipation can lead to possible bowel obstruction, which is estimated to be the third most common gastrointestinal emergency during pregnancy with an incidence of 1 in 2,500 deliveries (behind appendicitis and gallstones). Pregnant women commonly present with bowel obstruction in the third trimester, likely due to the uterus causing additional digestive issues/pressure on top of hormonal effects.
Women with constipation, nausea, vomiting, and/or abdominal pain should call their HCP.
Drinking water is frequently recommended to relieve and prevent constipation. Evidence suggests, however, that increasing fluids is only useful when women are constipated due to dehydration; therefore, additional fluid intake in women who are adequately hydrated may not offer any further benefit.
However, additional fluid can help with the digestion of fiber, especially if women have just recently started adding it to their diet.
The addition of fiber-rich foods can make a big difference in constipation symptoms and frequency of recurrence (read Fiber for more information).
Physical exercise is also known to help speed up digestion.
Straining, stalling, and delaying of bowel movements should also be avoided which can cause significant discomfort along with possible hemorrhoids and tearing.
If constipation is severe, and dietary changes have little effect, women should talk to their HCP regarding over-the-counter (OTC) medications.
Women should always talk to their HCP before taking any medications while pregnant, including OTC. It is very important that only the recommended dose be taken and an HCP should be notified if symptoms persist.
Different types of laxatives include bulk-forming agents, stool softeners, osmotic laxatives, and stimulant laxatives. Although very few laxatives have been studied in pregnancy, short term use is not expected to cause fetal abnormalities or pregnancy-related concerns due to low absorption.
Bulk-forming laxatives (Metamucil®) are considered safe during pregnancy even for long-term use. These laxatives increase bulk and moisture in stool that stimulates bowel activity. However, they can take several days to work and cause gas, bloating, and cramping. Bulk-forming laxatives work similarly to fiber-rich foods.
Stool softeners (Colace®) are considered safe during pregnancy. Stool softeners moisten the stool and make it easier to pass and are usually given to most women immediately upon delivery to avoid postpartum constipation. However, stool softeners are unlikely to work very well for moderate to severe constipation unless combined with an osmotic or stimulant laxative.
Osmotic laxatives (MiraLAX®) draw water into the bowel to expand and soften the stool. When taken on an empty stomach, they can work in as little as two hours but can cause gas, bloating, and sodium retention. Osmotic laxatives are considered safe during pregnancy, but long-term use could cause nausea and may lead to electrolyte imbalances.
Stimulant laxatives (Dulcolax®) are considered safe and effective and take between six and twelve hours to work. Some studies recommend avoiding stimulant laxatives in pregnancy due to potential side effects for the mother such as electrolyte imbalances, abdominal cramps, and dehydration, therefore they are not recommended for long-term use. However, no adverse effects to the fetus have been documented.
Suppositories are laxatives which are administered through the rectum, work rapidly, and are recommended for short-term relief when oral laxatives have failed to work. Enemas and suppositories can be very helpful in cases of NVP when medication cannot be swallowed alone or with the necessary fluid required for some laxatives.
Women should talk to their HCPs about their constipation. This is a common symptom, and women should not be embarrassed to bring it up. HCPs can recommend additional lifestyle changes or OTC medications that can greatly relieve discomfort.
If women are still embarrassed to discuss it, they can share/forward this page to their HCP so the HCP knows to initiate the topic at their next appointment.
Women should try to implement the lifestyle modifications described above. While hydration may not relieve constipation, it is important during pregnancy overall, and it can provide the body enough water to digest fiber properly.
Women should always talk to their HCP before talking any over-the counter-medications during pregnancy, including stool softeners, laxatives, and fiber supplements.
Women should also consider sharing and submitting their experience below regarding constipation during pregnancy. This can help other women learn additional perspectives regarding this concern and how they can handle its resulting discomforts.