Pregnancy gas is almost universal, and the main culprit is progesterone. This hormone, which rises sharply from the first weeks of pregnancy and stays elevated until delivery, directly relaxes the smooth muscle lining your digestive tract. That slows everything down, giving gut bacteria more time to ferment food and produce gas. The result: more bloating, more burping, and more flatulence than you’re used to.
How Progesterone Slows Your Digestion
Progesterone doesn’t just vaguely “relax” things. It actively changes the signaling chemistry in your intestinal walls, suppressing the compounds that trigger muscle contraction while boosting those that promote relaxation. The net effect is a measurable drop in gut motility, the wave-like contractions that push food through your system.
Slower transit means food sits in your intestines longer. Bacteria in your colon have more time to break down undigested carbohydrates, and that fermentation produces hydrogen, methane, and carbon dioxide. You feel it as bloating, pressure, and the need to pass gas far more often than before you were pregnant.
A second hormone, relaxin, may add to the problem. Relaxin’s primary job is loosening ligaments and joints to prepare your body for birth, but its relaxing effect on smooth muscle can further reduce the tightening action your intestines rely on to move things along. That contributes to constipation, bloating, and indigestion.
Why It Gets Worse Later in Pregnancy
Early pregnancy gas is mostly hormonal, but the picture changes as your baby grows. By the second and especially the third trimester, the expanding uterus physically presses on your rectum and lower intestine, further slowing transit and making constipation worse. Constipation and gas feed each other: stool sitting in the colon gives bacteria even more material to ferment.
So while many women notice increased gas as early as six weeks, the combination of high progesterone, physical compression, and constipation tends to make the third trimester the peak of discomfort.
Your Prenatal Vitamins May Be Contributing
Iron, a standard ingredient in most prenatal supplements, is a well-known cause of gastrointestinal side effects including nausea and constipation. When constipation worsens, gas typically follows. Research from Oregon Health & Science University found that for the average pregnancy, extra iron supplementation beyond what’s in a standard prenatal vitamin may not even be necessary, and its GI side effects can compound symptoms you’re already dealing with. If you suspect your supplement is making things worse, it’s worth asking your provider whether a lower-iron formula or a different form of iron could help.
Positions and Movements That Help
Certain body positions can physically help trapped gas move through your system. These work best when gas feels stuck and you’re dealing with uncomfortable pressure rather than just frequent flatulence.
- Child’s pose: Start on all fours, then sit your hips back toward your heels while reaching your arms forward and lowering your forehead toward the floor. Hold for 30 seconds up to a few minutes. Let your belly rest gently on the mat or between your legs.
- Knee-to-chest pose: Sometimes called the “wind-relieving pose” for good reason. Lie on your back, pull your knees toward your chest, and tuck your chin. Keep this brief, especially later in pregnancy, since lying on your back for extended periods isn’t recommended.
- Gentle squats: Stand with feet wide, toes pointing slightly out, and lower yourself slowly. Hold a wall or counter for stability. This opens the pelvis and can encourage gas to move.
- Seated forward fold: Sit with legs straight (or apart for comfort), then slowly hinge forward from the hips. The gentle compression on your abdomen can help release trapped gas.
- Gentle twists: Twisting your torso while seated puts mild pressure on your core and can get things moving. Keep these slow and avoid deep twists as your belly grows.
Dietary Adjustments That Actually Work
The foods most likely to increase gas are the ones that reach your colon undigested: beans, lentils, broccoli, cabbage, Brussels sprouts, onions, and whole grains. These are also nutritious foods you shouldn’t necessarily eliminate, but you can manage portions and preparation. Cooking vegetables thoroughly, for example, breaks down some of the fibers that cause fermentation.
Carbonated drinks add gas directly to your digestive system. Eating quickly does the same by increasing the amount of air you swallow. Slower meals, smaller portions spread across the day, and drinking water between meals rather than during them can all make a noticeable difference.
You might wonder about a low-FODMAP diet, which is commonly recommended for irritable bowel syndrome. Monash University, the research group that developed the diet, specifically does not recommend starting it during pregnancy. It’s a restrictive elimination diet, and pregnancy isn’t the right time to cut out broad categories of foods you and your baby may need.
Safe Over-the-Counter Relief
Simethicone, the active ingredient in products like Gas-X, works entirely within the gut and doesn’t enter your bloodstream. The NHS confirms it’s safe to take during pregnancy. It works by breaking up gas bubbles so they’re easier to pass, which can help with that uncomfortable bloated-balloon feeling. Just check that the product you’re buying contains only simethicone and not a combination of ingredients, since some multi-symptom formulas include other medications that may not be pregnancy-safe.
When Gas Pain Isn’t Just Gas
Normal pregnancy gas comes and goes, shifts around your abdomen, and resolves after you pass gas or have a bowel movement. What’s not normal is sharp, stabbing belly pain that doesn’t go away, pain that starts suddenly and gets progressively worse, or severe pain in your chest, shoulder, or back. The CDC lists these as urgent maternal warning signs that need immediate evaluation. Persistent one-sided lower abdominal pain in early pregnancy could signal an ectopic pregnancy, while severe upper abdominal pain later on can be associated with liver complications of preeclampsia. If the pain feels different from typical gas pressure, or if something just doesn’t feel right, that’s worth a call to your provider rather than waiting it out.