Pregnancy increases gas production and makes it harder for your body to hold it in, thanks to a combination of hormonal shifts, physical compression of your digestive organs, and changes in your gut bacteria. It’s one of the most common (and least discussed) pregnancy symptoms, and it typically gets worse as pregnancy progresses.
Hormones Slow Your Digestion Down
The primary driver of pregnancy gas starts early, well before your belly is visibly growing. Progesterone, which surges to support the pregnancy, relaxes smooth muscle throughout your body, including the muscles lining your intestinal walls. These muscles normally contract in rhythmic waves to push food through your digestive tract. When they relax, everything moves more slowly, and food sits in your gut longer. The longer food lingers, the more time bacteria have to ferment it and produce gas.
A second hormone called relaxin compounds the problem. Relaxin loosens the muscles and ligaments around your pelvis, back, and abdomen to prepare your body for delivery. But its relaxing effect isn’t limited to your pelvis. It also reduces the tightening action of your intestines, which can cause constipation, bloating, and indigestion. Between progesterone and relaxin, your entire digestive system is operating in slow motion for much of pregnancy.
Your Growing Uterus Crowds Your Organs
By the third trimester, your uterus occupies space that normally belongs to your small and large intestines, stomach, bladder, and liver. This physical compression squeezes your colon and further slows the movement of digested food. It also makes it harder for gas to pass through your intestines at a normal pace, so it builds up and eventually comes out in larger, more noticeable bursts.
This crowding is also why heartburn and indigestion tend to peak in late pregnancy. Your stomach has less room to expand, and your intestines are working in tighter quarters. The combination of hormonal slowing and physical compression is why many women notice gas getting progressively worse from the second trimester onward.
Your Gut Bacteria Change Too
Pregnancy doesn’t just affect your organs and hormones. It reshapes the bacterial ecosystem living in your gut. By the third trimester, the composition of gut bacteria shifts significantly. Research from Harvard Medical School found that women in their third trimester had notably different bacterial populations compared to non-pregnant people, with certain species becoming far more abundant.
Two bacterial species that increase during pregnancy, Gordonibacter pamelaeae and Eggerthella lenta, perform chemical transformations that require hydrogen, one of the gases other bacteria produce during normal digestion. In other words, the bacteria that thrive during pregnancy are actively consuming and producing byproducts of the same gas-generating processes happening in your gut. The researchers noted that gut bacterial processes are “significantly affected by, basically, flatulence,” highlighting how deeply intertwined gas production and the pregnancy microbiome really are.
Foods That Make It Worse
Certain foods produce more gas than others during digestion, and pregnancy amplifies the effect because food spends longer in your system. The usual culprits include beans, lentils, broccoli, cabbage, Brussels sprouts, onions, and whole grains. Carbonated drinks add gas directly to your digestive tract. Dairy can be a problem too, since some women develop temporary lactose sensitivity during pregnancy even if they tolerated dairy fine before.
Eating large meals makes things worse because your compressed stomach and sluggish intestines can’t process big volumes efficiently. Smaller, more frequent meals give your digestive system less to deal with at once. Eating slowly and chewing thoroughly also helps, since swallowing air while eating quickly is a surprisingly common source of intestinal gas.
What Actually Helps
Gentle movement is one of the most effective ways to get gas moving through your system. Walking after meals stimulates intestinal contractions and helps food (and gas) progress through your digestive tract. A few specific positions can also provide relief:
- Child’s pose: Kneeling and stretching your arms forward while lowering your chest toward the ground stimulates the abdominal organs and can help release trapped gas.
- Knees to chest: Lying on your back and pulling your knees gently toward your chest applies light pressure to your abdomen, easing gas and bloating. This works well before bed or first thing in the morning.
- Gentle twists: Starting on your hands and knees and sliding one arm under the opposite arm while twisting through your torso can loosen tension that slows digestion. (In later pregnancy, keep twists gentle and avoid deep rotation.)
Simethicone, the active ingredient in many over-the-counter gas relief products, does not cross the placenta and is generally regarded as safe during pregnancy. It works by breaking up gas bubbles in your intestines so they’re easier to pass. Staying well hydrated and getting enough fiber can help prevent the constipation that often worsens gas buildup, though adding fiber too quickly can temporarily increase gas before things improve.
When Gas Pain Feels Like Something More
Normal pregnancy gas can occasionally cause sharp, crampy pains that feel alarming but pass once the gas moves. The key distinction is that gas pain shifts location, comes and goes, and resolves after you pass gas or have a bowel movement.
Abdominal pain that is constant, severe, or one-sided in early pregnancy could signal something more serious. Pain accompanied by shoulder tip pain (felt where your shoulder ends and your arm begins), dizziness, fainting, or feeling very sick warrants immediate medical attention, as these can be signs of an ectopic pregnancy or other complication. Some changes in bowel patterns are normal during pregnancy, but persistent or severe symptoms are worth mentioning at your next appointment.
For the vast majority of pregnant women, increased gas is simply one of the less glamorous side effects of growing a human. It peaks in the third trimester when hormonal effects, organ compression, and microbiome shifts are all at their strongest, and it resolves after delivery as your body returns to its pre-pregnancy state.