Bulk-forming fiber supplements are the usual first step, followed by osmotic laxatives such as polyethylene glycol (commonly sold as MiraLAX) or lactulose if fiber alone does not help. Stool softeners like docusate sodium are widely used as well, though evidence for their effectiveness is thin. The options expand from there, but pregnancy narrows the field in important ways because some common remedies carry real risks to a developing baby.
Why Pregnancy Makes Constipation So Common
Constipation is one of the most frequent complaints during pregnancy, and it has several overlapping causes. The primary driver is progesterone, the hormone that rises sharply to support the pregnancy. Progesterone relaxes smooth muscle throughout the body, including the muscles that push food through the intestines. Research indicates that progesterone does this partly by increasing nitric oxide production, which causes the gut wall to relax and slow down.1PubMed Central. Progesterone inhibitory role on gastrointestinal motility The result is slower transit time, which means the colon absorbs more water from stool, leaving it harder and more difficult to pass.
Iron supplements, found in most prenatal vitamins, make the problem worse. A study that followed pregnant women longitudinally found that iron supplement use more than tripled the odds of constipation.2Obstetrics & Gynecology. Constipation in Pregnancy: Prevalence, Symptoms, and Risk Factors The growing uterus also puts physical pressure on the rectum later in pregnancy, and many women become less physically active as pregnancy progresses, which further slows things down. Understanding these causes matters because some of the best treatments target the cause directly rather than just forcing a bowel movement.
Start with Fiber and Fluids Together
Every clinical guideline puts dietary changes first, before any medication. That means eating more fiber-rich foods like fruits, vegetables, beans, and whole grains, or adding a fiber supplement such as psyllium husk (sold as Metamucil and generics). Fiber supplements are not absorbed into the bloodstream, so they carry essentially no risk to the pregnancy. They work by drawing water into the stool and adding bulk, which stimulates the intestines to move things along.
Here is the catch that many people miss: fiber without adequate fluid can actually make constipation worse. One study of pregnant women found that high fiber intake alone did not protect against constipation, but the combination of low fiber and low fluid intake dramatically increased the risk, nearly sixfold.3PubMed Central. Association of dietary fiber, liquid intake and lifestyle characteristics with gastrointestinal symptoms and pregnancy outcome A separate cross-sectional study confirmed this, finding that both higher dietary fiber and higher fluid intake independently reduced constipation risk during pregnancy.4PubMed. Functional constipation in pregnancy and its association with dietary intake and physical activity: a cross-sectional study Most guidance suggests aiming for around 25 to 30 grams of fiber per day and drinking at least eight glasses of water, though your individual needs may vary.
A review of constipation treatments in pregnancy noted that evidence supporting fiber supplements specifically is limited but positive, while the evidence for fluid intake alone is weaker. The review still recommended increased fluids as a sensible first measure given its other health benefits during pregnancy.5PubMed Central. Constipation, haemorrhoids, and heartburn in pregnancy In practice, this means fiber supplements plus plenty of water is your safest, lowest-risk starting point. Give it a week or two before deciding it is not working.
Osmotic Laxatives When Fiber Is Not Enough
If fiber and fluids do not resolve the problem within a couple of weeks, osmotic laxatives are the most commonly recommended next step. These work by pulling water into the intestines, softening the stool and making it easier to pass. The two you will encounter most often are polyethylene glycol (PEG, sold as MiraLAX or RestoraLAX) and lactulose (a prescription in some countries, over-the-counter in others).
A randomized controlled trial that directly compared PEG and lactulose in pregnant women found that both were effective by the end of treatment, with no significant difference in outcomes. PEG did appear to work somewhat faster, showing better improvement in constipation scores at the one- and two-week marks.6PubMed. A comparison of the safety and efficacy of polyethylene glycol 4000 and lactulose for the treatment of constipation in pregnant women: a randomized controlled clinical study Lactulose can cause more bloating and gas than PEG, which is worth knowing when nausea is already an issue during pregnancy. Neither is absorbed systemically in meaningful amounts, which is why both are considered low-risk.
PEG is typically mixed into a glass of water and taken once daily. The dose can be adjusted up or down depending on how you respond. Lactulose is a sweet syrup, usually taken once or twice daily. Both are meant for short- to medium-term use. If you find yourself needing them continuously for weeks, that warrants a conversation with your provider about whether something else is going on.
Stool Softeners
Docusate sodium, sold as Colace and many generic versions, is probably the single most commonly recommended product for constipation during pregnancy. It works as a surfactant, helping water and fat mix into the stool so it passes more easily. Doctors have been recommending it for decades, and it is generally considered safe in pregnancy.
The honest picture, though, is that the evidence supporting docusate’s effectiveness is surprisingly weak even outside of pregnancy. Multiple reviews have questioned whether it works much better than placebo. A review of laxative safety profiles in pregnant women acknowledged the widespread use of docusate but did not find robust evidence of efficacy.7Journal of Clinical Gastroenterology. Review of the Safety Profiles of Laxatives in Pregnant Women It may be worth trying since the safety profile is reassuring and the cost is low, but if it is not helping after a few days, moving to an osmotic laxative is a reasonable next step rather than continuing something that may not be doing much.
Stimulant Laxatives and When They Are Appropriate
Stimulant laxatives, which include senna (Senokot) and bisacodyl (Dulcolax), work by directly triggering the muscles of the intestinal wall to contract. They are more powerful than osmotic laxatives and tend to produce results within 6 to 12 hours. For occasional use when you are really stuck, they are considered acceptable during pregnancy.
The key word is occasional. A review in Canadian Family Physician recommended that both osmotic and stimulant laxatives be used only short-term or intermittently during pregnancy to avoid dehydration or electrolyte imbalances.8PubMed Central. Treating constipation during pregnancy Regular stimulant laxative use can also lead to the bowel becoming dependent on them, which creates its own cycle of problems. Think of senna or bisacodyl as a rescue option for a bad day, not as your daily management strategy. If you are reaching for them more than once or twice a week, your provider needs to reassess your overall plan.
What You Should Absolutely Avoid
Some remedies that seem natural or harmless are genuinely dangerous during pregnancy. The biggest offender is castor oil, which has a long folk reputation as a constipation cure and labor inducer. It can trigger uterine contractions and should never be used. A review of gastrointestinal medications in pregnancy listed castor oil, along with bismuth subsalicylate (Pepto-Bismol), among medications that should never be used due to clear risk of harm.9ScienceDirect. Gastrointestinal medications in pregnancy
Herbal laxatives deserve special caution. Many people assume “herbal” means “safe,” but several plant-based laxatives carry known reproductive risks. Rhubarb root contains emodin, which has caused fetal abnormalities in animal studies, and no human safety data exists. Fenugreek, sometimes marketed for digestive support, has been associated with birth defects in both human and animal data.10PubMed. Herbal laxatives and antiemetics in pregnancy Aloe vera juice taken orally can have stimulant laxative effects and contains anthraquinones whose safety in pregnancy is not established. The safest approach is to avoid any herbal laxative product unless your provider has specifically reviewed its ingredients and approved it.
Mineral oil, sometimes used for constipation in non-pregnant adults, is also best avoided during pregnancy. It can interfere with the absorption of fat-soluble vitamins (A, D, E, and K), which are critical during fetal development. Saline laxatives containing high doses of magnesium or sodium phosphate can cause fluid and electrolyte shifts that are poorly tolerated during pregnancy.
Rethinking Your Prenatal Vitamin
Since iron supplements are one of the strongest risk factors for constipation during pregnancy, one practical strategy is to look at what kind of iron your prenatal vitamin contains and how much. A randomized crossover trial compared a prenatal supplement with a lower dose of iron (given separately from calcium) against a standard high-iron prenatal vitamin. The low-iron formulation was associated with roughly 30% less constipation.11PubMed Central. A randomized cross over trial of tolerability and compliance of a micronutrient supplement with low iron separated from calcium vs high iron combined with calcium in pregnant women
This does not mean you should stop taking iron. Iron deficiency anemia during pregnancy carries its own serious risks. But if constipation is making you miserable, talk to your provider about whether you could switch to a prenatal vitamin with a lower iron dose, a different form of iron (some forms like iron bisglycinate are easier on the gut), or a slow-release formulation. Taking your iron supplement with food, though it slightly reduces absorption, can also ease gastrointestinal side effects. Some women benefit from splitting the dose across the day rather than taking it all at once.
Probiotics as an Emerging Option
Probiotic supplements have drawn increasing research attention for constipation during pregnancy, and the early results are encouraging. A study that gave pregnant women a specific probiotic combination found significant improvements in how often women had bowel movements, how long they spent trying, and stool consistency. The researchers attributed the benefit to the probiotics restoring diversity in the gut microbiome, which pregnancy and constipation both tend to disrupt.12PubMed. Probiotics combination effectively improves constipation in pregnancy by modifying the gut microbiota composition
The research is still in early stages, and there is no consensus yet on which strains, doses, or durations work best. Not all probiotics are the same, and a product marketed for “digestive health” may contain strains that have no evidence for constipation specifically. Lactobacillus and Bifidobacterium species are the most commonly studied for this purpose. Probiotics are generally considered safe during pregnancy, but they are unlikely to provide dramatic relief on their own. They may work best as part of a broader strategy alongside fiber, fluids, and other measures.
A Practical Order of Operations
With all these options, it helps to think about treatment as a stepwise approach rather than jumping straight to medication. Most providers would recommend this rough sequence:
- Step one: Increase fiber intake to 25-30 grams daily through food or a psyllium supplement, drink plenty of water, and stay as physically active as you comfortably can.
- Step two: If the problem persists after a week or two, add an osmotic laxative like PEG daily, or try lactulose.
- Step three: If osmotic laxatives alone are not enough, try adding a stool softener like docusate, though expectations should be modest.
- Step four: For occasional acute episodes, a stimulant laxative like senna or bisacodyl can provide relief, but keep it to short-term use.
Throughout all of these steps, reassessing your iron supplement remains worthwhile if it seems to be a major contributor. And if you are still struggling despite working through these options, your provider may want to rule out other causes of constipation that can occasionally emerge during pregnancy, such as thyroid problems or mechanical obstruction.
Hemorrhoids and Why Early Treatment Matters
Constipation during pregnancy is not just uncomfortable. It is one of the primary drivers of hemorrhoids, which affect a substantial number of pregnant women, especially in the third trimester. Straining to pass hard stool puts pressure on the veins around the rectum, and the increased blood volume and weight of the uterus during pregnancy make those veins even more vulnerable. A Cochrane review found that the most commonly used approaches for hemorrhoids during pregnancy, including dietary changes and topical treatments, have not been properly evaluated in clinical trials.13Cochrane Library. Conservative management of symptomatic and/or complicated haemorrhoids in pregnancy and the puerperium This means prevention by managing constipation early is your best bet, since treating hemorrhoids once they develop has a weaker evidence base.
Topical treatments containing witch hazel or a local anesthetic can ease hemorrhoid symptoms when they do occur. Sitting in warm water (a sitz bath) for 10 to 15 minutes can also reduce swelling and discomfort. But the real priority is softening your stool so you stop straining, which is where the constipation treatments above do double duty.
Constipation After Delivery
Many women expect constipation to end with delivery, but it often gets worse in the immediate postpartum period. Pain from a cesarean incision or perineal tear makes it harder to bear down. Opioid pain medications slow the gut. Dehydration from labor and breastfeeding compounds the problem. And psychologically, the fear of pain during a bowel movement after vaginal delivery is a real and understandable barrier.
A Cochrane review of interventions for preventing postpartum constipation found that a laxative given after delivery, specifically senna, nearly tripled the number of women who had a bowel movement within 24 hours. It also substantially reduced the number of women still waiting by day two or three. However, the review noted that senna also increased the rate of abdominal cramps.14PubMed Central. Interventions for preventing postpartum constipation The evidence was rated low certainty, and it came from a single large trial, so it is not definitive. Still, many hospitals now routinely offer a stool softener or a gentle laxative after delivery, especially after cesarean sections. If yours does not, it is worth asking.
Breastfeeding mothers sometimes worry about laxatives passing into breast milk. Bulk-forming agents like psyllium are not absorbed and pose no concern. PEG is also not absorbed. Senna can pass into breast milk in tiny amounts, but the quantities are generally considered too small to affect the baby. Docusate is similarly considered compatible with breastfeeding. The bigger concern postpartum is making sure you are drinking enough water, especially if breastfeeding is increasing your fluid needs. Constipation that persists beyond the first few weeks postpartum warrants a check-in with your provider, as pelvic floor dysfunction from delivery can sometimes interfere with normal bowel function in ways that laxatives cannot fix on their own.