Several over-the-counter options are considered safe for constipation during pregnancy, starting with bulk-forming fiber supplements and stool softeners as first choices. Up to 40% of pregnant women experience constipation at some point, mostly due to hormonal shifts that slow digestion and the physical pressure of a growing uterus. The good news is that a combination of dietary changes and gentle remedies can bring relief without posing risks to your baby.
Why Pregnancy Causes Constipation
Rising progesterone levels relax smooth muscle throughout your body, including the muscles that move food through your intestines. This slows the whole digestive process, giving your colon more time to absorb water from stool and leaving it harder and more difficult to pass. Iron supplements, which many pregnant women take, can make the problem worse. As pregnancy progresses, the expanding uterus adds physical pressure on the bowel, which further slows things down, especially in the third trimester.
First-Line Options: Fiber Supplements and Stool Softeners
Bulk-forming fiber supplements like psyllium (sold as Metamucil) and wheat bran are the go-to starting point. They work by absorbing water in your intestines, which increases stool bulk and makes it softer and easier to pass. These supplements are not absorbed into your bloodstream and are not associated with an increased risk of birth defects, making them safe for long-term use throughout pregnancy. They typically take one to three days to start working. Drink a full glass of water with each dose to prevent bloating.
Stool softeners containing docusate sodium (Colace) are another common first choice. They help water and fats mix into the stool so it passes more easily. Like fiber supplements, docusate is minimally absorbed and widely considered safe during pregnancy. Many OB-GYNs recommend it as a daily option when fiber alone isn’t enough.
Osmotic Laxatives for Stubborn Cases
If fiber and stool softeners aren’t doing the job after a few days, osmotic laxatives are the next step. These work by drawing water into the intestines to soften stool. Polyethylene glycol 3350 (MiraLAX) is the most commonly recommended option in this category. It’s poorly absorbed, meaning very little enters your bloodstream, and it generally produces a bowel movement within one to three days.
Milk of Magnesia (magnesium hydroxide) is another osmotic option that works somewhat faster, often within six hours. It’s generally considered safe for short-term, occasional use during pregnancy. Because magnesium in large or prolonged doses could potentially cause electrolyte imbalances, it’s best used as a now-and-then remedy rather than a daily one.
Stimulant Laxatives: Use With Caution
Stimulant laxatives like senna (Senokot) and bisacodyl (Dulcolax) are considered second-line treatments. They work by triggering contractions in your intestinal muscles to push stool along. While short-term, occasional use is generally considered acceptable when gentler options have failed, these aren’t recommended for regular use during pregnancy. There’s a theoretical concern that stimulating intestinal contractions could also stimulate uterine activity, though this hasn’t been well demonstrated at standard doses. Senna also shows up in some herbal teas marketed for digestion, so check ingredient labels.
What to Avoid
Castor oil is one product you should skip entirely. It’s a powerful stimulant that can trigger uterine contractions and has been historically used to try to induce labor. Mineral oil is also best avoided during pregnancy because long-term use can interfere with the absorption of fat-soluble vitamins (A, D, E, and K) that are critical for fetal development. Saline laxatives containing sodium phosphate (like Fleet enemas) carry a risk of electrolyte shifts and dehydration, making them a poor choice during pregnancy without direct medical guidance.
Dietary and Lifestyle Changes That Help
Before reaching for any supplement, dietary adjustments can make a real difference and are worth trying first. Aim for 20 to 35 grams of fiber per day from food sources like fruits, vegetables, beans, whole grains, and oats. For reference, a cup of cooked lentils has about 15 grams, a pear has 6, and a cup of broccoli has about 5. Building up gradually over a week or two helps you avoid the gas and bloating that can come with a sudden jump in fiber intake.
Water intake matters just as much. The American College of Obstetricians and Gynecologists recommends drinking 8 to 12 cups (64 to 96 ounces) of water daily during pregnancy. Water aids digestion, helps form amniotic fluid, and keeps stool soft enough to pass comfortably. If you’re also taking a fiber supplement, you need that water even more, since fiber without adequate fluid can actually worsen constipation.
Regular physical activity, even a 20 to 30 minute walk each day, stimulates the natural muscle contractions of the intestines. Many women notice a significant improvement from walking alone, particularly in the second and third trimesters when constipation tends to peak.
Probiotics as a Possible Add-On
Emerging evidence suggests certain probiotic strains may help with pregnancy constipation. A pilot study published in the Nutrition Journal tested a mixture of Bifidobacterium and Lactobacillus strains in constipated pregnant women over four weeks. Participants experienced a significant increase in how often they had bowel movements, along with less straining, less abdominal pain, and fewer episodes of feeling like they hadn’t fully emptied. No adverse effects were reported. The evidence is still preliminary and needs confirmation from larger trials, but probiotics are generally safe during pregnancy and may be worth trying alongside other approaches. Look for products that contain Bifidobacterium and Lactobacillus species, which have the most supporting data.
A Practical Order of Operations
A reasonable approach looks like this:
- Start with diet and water. Increase fiber to 25+ grams daily, drink at least 64 ounces of water, and add daily movement.
- Add a fiber supplement or stool softener. Psyllium or docusate sodium are safe for daily use and often enough to get things moving within a few days.
- Try an osmotic laxative. Polyethylene glycol is the most common next step if the above isn’t sufficient.
- Reserve stimulant laxatives for occasional use. Senna or bisacodyl can help in a pinch but shouldn’t become routine.
If you’re also taking a prenatal vitamin with iron and constipation is persistent, ask your provider about switching to a form of iron that’s easier on digestion, or adjusting when and how you take it. Sometimes that single change resolves the problem. If constipation lasts longer than three weeks, involves rectal bleeding, blood in your stool, or stomach pain that won’t let up, those warrant a call to your provider to rule out something beyond routine pregnancy constipation.