Diarrhea during pregnancy

By trimester

Weeks 1–13

1st trimester

Diarrhea in the first trimester often overlaps with morning sickness and can come from hormones, a virus, or something you ate. It's rarely a concern on its own, but it adds to your fluid loss if you're also vomiting. Stick to water, an electrolyte drink, and bland foods, and mention it at your next visit if it lingers beyond a few days.

Weeks 14–27

2nd trimester

Once early hormonal swings settle down, a stomach bug or something you ate, like a new prenatal vitamin or a rich meal, is usually the cause. Fluids and electrolytes are still the first response. If symptoms persist or get worse, call rather than wait it out.

Weeks 28–birth

3rd trimester

Looser, more frequent stools in the final days before labor are common, likely tied to the same hormones that help ripen the cervix. Dehydration can add to third-trimester fatigue and may irritate the uterus, so get ahead of it with fluids, and call your provider promptly if diarrhea comes with contractions, fever, or less fetal movement.

What does the evidence show for diarrhea?

• Diarrhea caused by pregnancy itself may come from rising prostaglandin levels, a hormonal cause separate from an infection or something you ate. 1
• Constipation and diarrhea together are among the most common digestive complaints in pregnancy, affecting up to about a third of pregnant women, and diarrhea in pregnancy usually has the same causes it would outside of pregnancy. 2
• Infections, food allergies or intolerances, other digestive issues, and medication side effects are the general causes of diarrhea, and all of these can still apply during pregnancy alongside hormonal shifts. 3
• Replacing lost fluids and electrolytes is the core response to short-term diarrhea, and it's worth getting checked out if it lasts longer than about a week or comes with other symptoms. 3
• Bismuth subsalicylate, the active ingredient in Pepto-Bismol and Kaopectate, is specifically flagged to avoid during pregnancy, which is why any over-the-counter antidiarrheal is worth a quick check with your provider rather than assumed to be safe. 4
• Diarrhea lasting more than 2 days, six or more loose stools in a day, a high fever, black or tarry stools, blood or pus in the stool, severe abdominal or rectal pain, frequent vomiting, or dehydration signs like a dry mouth, reduced urination, dark urine, or skin that stays tented when pinched all call for prompt medical evaluation. 5

When should I call my provider about diarrhea?

Call the same day for diarrhea lasting more than 2 days, six or more loose stools in a day, a high fever, or stools that are black and tarry or contain red blood or pus. Severe abdominal or rectal pain and frequent vomiting are two more signs this needs a same-day look rather than home fluids alone. Dehydration signs, like a dry mouth, urinating much less than usual, dark urine, or skin that stays tented when pinched, mean you need more fluids than you can likely manage on your own. Trust your read on your own body. If something feels off beyond the list above, please consult your healthcare provider rather than waiting it out.