Constipation affects roughly half of all pregnant women at some point, and it’s one of the most predictable discomforts of pregnancy. The good news: a combination of dietary changes, hydration, movement, and the right supplements can prevent most cases or significantly reduce their severity. Here’s what actually works and why pregnancy makes your gut slow down in the first place.
Why Pregnancy Slows Your Digestion
The hormone progesterone rises sharply during pregnancy to support the uterus, but it also acts directly on the muscles of your digestive tract. Your colon has specialized cells that control the rhythm of contraction and relaxation. Progesterone weakens the cells responsible for contraction while boosting the ones that promote relaxation. The result is that food waste moves through your colon much more slowly than usual, giving your body extra time to absorb water from stool and leaving it hard and difficult to pass.
On top of that hormonal shift, prenatal vitamins add another layer. The iron in most prenatal formulas is a well-known contributor to constipation. And as your uterus grows, it physically presses on your intestines, further slowing things down. Understanding these causes helps explain why prevention requires a multi-angle approach rather than a single fix.
Eat More Fiber (and the Right Kinds)
Pregnant women need about 25 to 28 grams of fiber per day. Most people don’t come close to that number on a typical diet, so you’ll likely need to make deliberate changes. The key is to increase fiber gradually over a week or two, since adding too much at once can cause gas and bloating that make you feel worse before you feel better.
Focus on a mix of soluble and insoluble fiber. Soluble fiber (found in oats, beans, lentils, and citrus fruits) absorbs water and forms a gel that softens stool. Insoluble fiber (found in whole wheat bread, vegetables, and bran) adds bulk and helps waste move through the colon faster. Some of the most effective foods combine both types:
- Prunes and prune juice: These contain fiber plus a natural sugar alcohol called sorbitol. Sorbitol doesn’t break down during digestion, and when it reaches the colon, it draws water in and triggers a bowel movement. This makes prunes essentially a natural osmotic laxative.
- Pears and apples: Both are high in fiber and contain some sorbitol (apple juice has it in lower amounts than prune juice, but it still helps).
- Beans and lentils: A half-cup of cooked lentils provides about 8 grams of fiber, making them one of the most efficient sources.
- Berries, broccoli, and sweet potatoes: Easy to add to meals and snacks throughout the day.
If you’re struggling to hit 25 grams through food alone, a fiber supplement like psyllium husk can fill the gap. It’s a bulk-forming fiber that isn’t absorbed by the body and is considered safe during pregnancy.
Drink Enough Fluids
Fiber only works well if you’re drinking enough water alongside it. Without adequate fluid, extra fiber can actually make constipation worse by creating dry, bulky stool that’s hard to pass. Aim for at least 1.6 liters of fluid per day, which works out to about six to eight glasses. Water is ideal, but herbal teas, milk, and diluted fruit juices count toward your total.
A practical habit: keep a water bottle with you and sip throughout the day rather than trying to catch up with large amounts at meals. If you’re exercising, sweating, or dealing with morning sickness that involves vomiting, you’ll need more than the baseline amount.
Stay Physically Active
Movement stimulates the muscles of your digestive tract in ways that sitting still simply doesn’t. Even moderate activity like a 20- to 30-minute walk most days can meaningfully reduce constipation. Swimming, prenatal yoga, and light cycling on a stationary bike are other options that are generally well tolerated throughout pregnancy.
You don’t need intense exercise for the benefit. The goal is consistent, daily movement. If you’ve been sedentary, starting with a 10-minute walk after meals and building from there is a reasonable approach.
Rethink Your Prenatal Vitamin
If constipation started or worsened around the time you began taking a prenatal vitamin, the iron content is the likely culprit. Standard prenatal vitamins often use forms of iron that are harder on the gut. You have a few options: some brands use gentler iron formulations like iron bisglycinate, which tends to cause less digestive upset. Another option is to take your prenatal with food or at a different time of day to see if that reduces the effect.
Don’t stop taking iron or switch supplements without talking to your provider, since iron needs increase significantly during pregnancy. But knowing that the vitamin itself could be part of the problem gives you something specific to address.
Consider Probiotics
There’s growing evidence that certain probiotic strains can help with pregnancy constipation specifically. In a pilot study of pregnant women who took a multi-strain probiotic containing several Bifidobacterium and Lactobacillus species for four weeks, bowel movement frequency more than doubled, going from about 3 times per week to nearly 7. The percentage of women who experienced straining dropped from 100% to 65%, and those reporting abdominal pain fell from 60% to 20%.
These are promising numbers, though the study was small. Probiotics that include Bifidobacterium longum, Lactobacillus rhamnosus, or Lactobacillus plantarum are the strains with the most relevant evidence. Yogurt and kefir provide some probiotics naturally, but a targeted supplement delivers higher concentrations of specific strains.
Safe Options When Prevention Isn’t Enough
Sometimes lifestyle changes alone don’t fully solve the problem, especially in the third trimester when hormonal effects and physical pressure on the intestines are at their peak. Several types of over-the-counter products are considered safe during pregnancy:
- Stool softeners: These work by drawing water into the stool to make it softer and easier to pass. They’re generally the first recommendation because they’re gentle and not absorbed into the bloodstream.
- Bulk-forming laxatives: Products containing psyllium or polycarbophil work like supplemental fiber. They aren’t absorbed by the body and are typically safe throughout pregnancy.
- Osmotic laxatives: These pull water into the colon. Magnesium hydroxide and lactulose are options in this category that are considered safe for pregnant women.
- Stimulant laxatives: These directly trigger colon contractions. They’re safe for occasional use but aren’t meant for daily, long-term prevention.
The general approach is to start with the gentlest option (more fiber, more water, a stool softener) and only escalate if needed. Your provider can help you decide which type makes sense for your situation.
Daily Habits That Make a Difference
Beyond the major strategies, a few smaller habits can help keep things moving. Eating smaller, more frequent meals rather than three large ones reduces the load on your digestive system at any given time. Responding to the urge to have a bowel movement right away, rather than waiting, helps maintain your body’s natural rhythm. Sitting with your feet elevated on a small stool (so your knees are above your hips) changes the angle of your colon and makes elimination easier.
Timing also matters. Many people find that their bowels are most active in the morning, especially after a warm drink. A cup of warm water with lemon or a small glass of prune juice first thing can help establish a predictable routine. Consistency with all of these habits matters more than perfection with any single one. Constipation during pregnancy is driven by multiple factors working together, and the most effective prevention strategy layers several approaches at once.