Pregnancy can change almost everything about your digestive system — and if you already have irritable bowel syndrome (IBS), figuring out which symptoms belong to pregnancy and which belong to IBS can get complicated fast.
Constipation may suddenly become your biggest problem even if it wasn’t before. Foods you normally tolerate may seem unappealing or trigger symptoms. Heartburn and bloating can appear out of nowhere. Or, surprisingly, some long-standing IBS symptoms may actually improve.
Then you have the postpartum period, when hormones shift again, your pelvic floor is recovering, sleep disappears, eating schedules become unpredictable and your bowel habits may change yet again.
The important thing to know is that digestive changes during pregnancy and after delivery are extremely common. Having IBS can add another layer, but it doesn’t mean you have to simply suffer through nine months — or beyond.
Here’s what may happen to your gut during pregnancy and postpartum, and what you can do to manage it safely.
Pregnancy can change your IBS — but there isn’t one predictable pattern
There is no single “pregnancy version” of IBS.
Some people find their IBS improves during pregnancy. Others experience more constipation, gas, bloating or abdominal discomfort. Still others find that their usual symptoms simply change.
And despite how common IBS is among women of reproductive age, researchers point out that there is still surprisingly little research specifically examining IBS during pregnancy.
What we do know is that pregnancy itself produces significant changes in gastrointestinal function.
Hormonal changes — particularly changes involving progesterone — can alter gastrointestinal motility. Meanwhile, as pregnancy progresses, the expanding uterus physically changes the space available to the digestive tract. Together, these changes can contribute to constipation, reflux and other gastrointestinal symptoms. A review of gastrointestinal conditions during pregnancy discusses these physiological changes and their effects on digestion.
That means a digestive symptom isn’t necessarily evidence that your IBS is “getting worse.” Your gut is functioning under a very different set of circumstances.
Constipation may become the biggest IBS challenge
Even people who don’t have IBS frequently develop constipation during pregnancy.
A recent systematic review and meta-analysis estimated that about one-third of pregnant women experience constipation, although prevalence varies across pregnancy.
There are several reasons.
Progesterone can slow intestinal movement. The growing uterus can create additional mechanical pressure. Activity levels may change. Dietary habits may change because of nausea or food aversions. And iron in prenatal vitamins can contribute to constipation in some people.
If you already have IBS with constipation (IBS-C), those changes can feel especially significant.
Fortunately, some of the basic tools for managing constipation remain useful during pregnancy.
Start with fluids and fiber
Adequate hydration matters, particularly as you increase fiber.
If you follow a modified low FODMAP diet, look for fiber-rich foods you already know you tolerate rather than drastically expanding or restricting your diet all at once.
Depending on your individual FODMAP tolerances and appropriate serving sizes, options might include oats, kiwi, chia seeds, certain nuts and seeds, potatoes, leafy greens, carrots and low FODMAP servings of legumes.
Fiber isn’t a magic switch, however. Suddenly adding large quantities can increase gas and bloating, particularly in someone with IBS. Increase it gradually and pay attention to how your body responds.
Our guide, The Scoop on Increasing Your Ability to Poop: Strategies for Alleviating Constipation, goes into much greater detail about fiber, bowel habits and constipation management.
Regular movement can help, too, as long as your obstetric provider has cleared you for physical activity.
And if dietary and lifestyle strategies aren’t enough, don’t simply start taking a laxative, magnesium product, herbal remedy or “natural” constipation supplement because you’ve used it before. Pregnancy changes the safety calculation. Ask your OB, midwife, physician or pharmacist which options are appropriate for you.
Diarrhea may change, too
Pregnancy isn’t synonymous with constipation.
People with diarrhea-predominant IBS (IBS-D) may notice that their bowel habits change — and some actually experience less diarrhea as gastrointestinal transit slows.
Monash University notes that some people with IBS-D report improvement during pregnancy and may discover they tolerate foods that previously caused problems.
If that happens, don’t assume you must continue avoiding a food simply because it was previously on your “IBS list.” Pregnancy may be an opportunity to discuss cautious reintroductions with a dietitian.
On the other hand, new or significant diarrhea shouldn’t automatically be dismissed as IBS. Infection, medication, dietary changes and other conditions can also cause diarrhea during pregnancy. Persistent or severe diarrhea — particularly with fever, bleeding, dehydration or significant pain — deserves medical attention.
Bloating and gas can feel more intense
Bloating is already one of the hallmark complaints associated with IBS, and pregnancy can add several additional factors.
Slower gastrointestinal transit can mean more time for gas to accumulate. Constipation can contribute to abdominal pressure. Your eating habits may change. And as pregnancy advances, distinguishing intestinal bloating from the normal physical sensations of pregnancy isn’t always straightforward.
This is where knowing your own IBS patterns can be useful.
Rather than responding to every uncomfortable day by eliminating another food, look for patterns. Did you dramatically increase fiber? Are you eating larger meals? Have you been constipated for several days? Did a familiar FODMAP trigger appear in several meals?
The goal is to troubleshoot — not continually shrink your diet.
Heartburn may be new even if you’ve never had it before
Reflux and heartburn are common during pregnancy and aren’t necessarily related to IBS at all.
Hormonal changes can affect gastrointestinal motility, while later in pregnancy the growing uterus increases pressure within the abdomen.
If heartburn becomes a problem, smaller meals may be more comfortable than very large ones. You may also find it helpful to avoid lying down immediately after eating and to identify your personal reflux triggers.
Remember that an IBS trigger and a heartburn trigger aren’t necessarily the same thing. A food may be perfectly low FODMAP and still aggravate reflux.
If symptoms are frequent or severe, ask your healthcare provider about pregnancy-safe treatment rather than unnecessarily restricting your diet.
Morning sickness can throw your normal IBS diet out the window
For some people, nausea and food aversions are a bigger nutritional challenge than IBS itself during early pregnancy.
The carefully planned breakfast you normally tolerate may suddenly make you gag. Vegetables may become impossible. The only food that sounds remotely appealing might be toast, crackers or potatoes.
This is not the time to aim for dietary perfection.
Eating smaller amounts more frequently may be easier than sitting down to large meals, and keeping tolerated foods readily available can help when nausea suddenly lifts enough to eat.
Our Pregnancy & IBS Series: Morning Sickness offers additional strategies specifically for people managing IBS and FODMAP concerns during this stage.
If vomiting is severe, you’re unable to keep fluids down, you’re losing weight or you’re worried about dehydration, contact your healthcare provider. Severe pregnancy nausea and vomiting can require medical treatment.
Pregnancy cravings can accidentally change your FODMAP load
Pregnancy cravings are another curveball.
Sometimes you’ll crave something that happens to work beautifully with your digestive system. Other times you may suddenly eat much larger quantities of a food than you normally would.
With FODMAPs, portion size matters.
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A food that you tolerate in one serving can potentially produce symptoms when the amount increases substantially or when several FODMAP-containing foods are eaten together.
The answer isn’t to be afraid of cravings. Just remember that if your IBS suddenly flares, it can be useful to look at how much you’re eating as well as what you’re eating.
Lactose can be another issue if ice cream, milk or other dairy foods suddenly become pregnancy staples. But don’t assume IBS means eliminating dairy. The low FODMAP diet is not dairy-free, and many dairy foods are naturally low in lactose or available in lactose-free versions. Our guide to lactose, dairy and the low FODMAP diet explains the distinction.
Should you start the low FODMAP diet while pregnant?
This is where pregnancy and ordinary IBS management diverge.
Pregnancy is not the time to independently begin the full low FODMAP Elimination Phase.
Monash University, which developed the low FODMAP diet, specifically states that it has not studied the low FODMAP diet in pregnant women and does not recommend commencing the diet during pregnancy.
Pregnancy increases nutritional demands at the same time that nausea, vomiting, food aversions and appetite changes may already make it harder to eat adequately. Adding an unnecessarily restrictive diet can make meeting those needs more difficult.
If you completed the Elimination and Challenge phases before becoming pregnant and already eat a personalized, expanded FODMAP diet, that’s different.
You may be able to continue eating according to your established tolerances, ideally with guidance from a Registered Dietitian familiar with both IBS and prenatal nutrition.
And pregnancy isn’t necessarily the time to be rigid about old tolerances. Your gut may behave differently now.
Our interview on pregnancy and the low FODMAP diet explores these nutritional considerations in greater depth.
Your IBS medications and supplements deserve another look
If you regularly use prescription medications, over-the-counter products, fiber supplements, laxatives, antidiarrheals, peppermint oil, probiotics, magnesium or herbal products to manage IBS, tell your prenatal healthcare provider.
“Over the counter” and “natural” don’t automatically mean safe during pregnancy.
Don’t discontinue a prescription medication without talking with the clinician who prescribed it, either. The safest approach is a medication-by-medication review that weighs the benefits of controlling your symptoms against any known pregnancy risks.
You may want to read: Medications & Supplements for IBS
Then comes delivery — and your gut changes again
Giving birth creates another major transition for your digestive system.
After delivery, bowel movements can temporarily become difficult for reasons that have nothing to do with your previous IBS pattern.
You may be dealing with dehydration, medications, reduced movement, hemorrhoids, perineal soreness, pelvic-floor changes or simply fear that having a bowel movement is going to hurt.
Cleveland Clinic notes that the first bowel movement after delivery may not occur until the third or fourth day.
If you have a history of constipation, it makes sense to discuss postpartum bowel management with your healthcare team before you leave the hospital or birth center.
Ask what you should do if you don’t have a bowel movement, whether a stool softener or other medication is appropriate, and when constipation warrants a call.
Don’t overlook the pelvic floor
Pregnancy and delivery don’t affect only the intestines.
The pelvic floor muscles help coordinate bowel movements, and pregnancy and childbirth can change how those muscles function.
If postpartum bowel movements require excessive straining, you constantly feel as though you haven’t completely emptied, you develop fecal leakage or bowel control problems, or constipation remains difficult despite appropriate diet and medication, tell your healthcare provider.
Pelvic-floor physical therapy can be an important part of treatment for some people. A bowel problem isn’t always solely a food problem — particularly after childbirth.
Postpartum IBS can be unpredictable
You might expect your digestive system to immediately return to its pre-pregnancy baseline after delivery. It may not.
Hormones are shifting again. Your abdominal and pelvic-floor muscles are recovering. Sleep is fragmented. Meal timing may become chaotic. You may be eating whatever can be consumed one-handed while holding a newborn.
And if you’re breastfeeding, your energy and nutrient requirements remain elevated.
In other words, postpartum life contains plenty of potential IBS disruptors.
Rather than immediately responding to symptoms with a highly restrictive diet, return to the IBS-management basics that have worked for you in the past: regular meals when possible, adequate fluids, appropriate fiber, movement as you’re able, and your established individual FODMAP tolerances.
Our Postpartum Nutritional Needs & IBS guide covers nutrition during this “fourth trimester,” including practical ways to stay fed when caring for a newborn.
Breastfeeding changes the nutritional equation again
If you’re breastfeeding, producing milk requires additional energy and nutrients.
This is another reason to avoid making your diet more restrictive than necessary.
Easy-to-grab meals and snacks can be invaluable. Think in terms of foods that combine energy, protein and nutrients rather than obsessing over constructing a perfect meal every time you eat.
Depending on your tolerances, that might mean lactose-free yogurt with fruit, eggs and toast, oatmeal with tolerated nuts or seeds, cheese and crackers, a smoothie, leftovers from dinner, or one of the many low FODMAP recipes you already know agrees with you.
Our complete guide to breastfeeding on a low FODMAP diet includes nutrient considerations and practical snack ideas for this stage.
When digestive symptoms shouldn’t be blamed on IBS
One of the risks of living with a chronic gastrointestinal condition is becoming accustomed to abdominal discomfort and altered bowel habits.
Pregnancy is a time to be particularly careful about assuming, “It’s just my IBS.”
Contact your obstetric or medical team if you develop symptoms that are new, severe, persistent or significantly different from your normal IBS pattern — particularly gastrointestinal bleeding, severe or worsening abdominal pain, persistent vomiting, inability to keep fluids down, signs of dehydration, fever or significant persistent diarrhea.
After delivery, seek medical guidance for severe abdominal or rectal pain, significant bleeding, inability to pass stool or gas, persistent bowel-control problems or other symptoms that concern you.
Your normal IBS history can provide context, but it shouldn’t prevent a new symptom from being evaluated.
The goal during pregnancy isn’t a perfect gut
IBS management often teaches us to pay very close attention to food, symptoms and bowel habits. Pregnancy can make that feel frustrating because the rules suddenly seem to change.
A food you’ve eaten happily for years might become revolting. Your previously reliable bowel schedule may disappear. Your FODMAP tolerance may shift. Then you give birth and everything changes again.
Instead of trying to force your digestive system to behave exactly as it did before pregnancy, focus on keeping yourself adequately nourished while managing symptoms as comfortably and safely as possible.
If you’re already following a personalized FODMAP diet, pregnancy may require some adjustments. If you’ve never tried the low FODMAP diet, this is generally not the time to undertake the restrictive Elimination Phase on your own.
And if your symptoms become difficult to manage, bring in help. A Registered Dietitian experienced in both gastrointestinal disorders and prenatal/postpartum nutrition can help you distinguish useful dietary adjustments from restrictions you simply don’t need.
Pregnancy, childbirth and postpartum recovery ask an extraordinary amount of the body.
Your gut gets to be a little unpredictable, too.
