Illustration by Marta Pucci
Digestion and your cycle: the truth about period poop
How does your digestion change on your period?
Have you ever found that everything you eat during the beginning of your period seems to upset your stomach? Do you find that gas is especially problematic right before you menstruate? Or do you notice bloating that can’t be explained by your diet? It’s not all in your head—your gastrointestinal system, or your stomach and intestines, is influenced by your menstrual cycle and can affect your digestion and stool (poop). Let’s talk about the whys and hows of menstrual cycle gastrointestinal changes.
Period poop is a real phenomenon
You’re more likely to hear about period cramps or menstrual fatigue when people talk about their period woes, but digestion can also change throughout the cycle and be bothersome. Women and people with cycles often report abdominal pain, diarrhea, indigestion, constipation, and reflux around the time of their periods, particularly on the first day of bleeding (1, 2). People with existing irritable bowel syndrome (IBS) may have aggravated gastrointestinal distress, leading up to and during their period (3).
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Chemicals called prostaglandins can cause period diarrhea
Menstruation occurs due to the normal localized process of inflammation in the uterus (4). This inflammation helps the tissue that we call the endometrial lining break down (4). As the tissue breaks down, it exits through the vagina as the bleeding that we call the period (4, 5).
How does this work? The reproductive hormone progesterone is anti-inflammatory (4). This hormone declines as you near your period, triggering an inflammatory state in the uterus (4, 5). Pro-inflammatory chemical-messengers called prostaglandins then act on the uterus (4, 5). This triggers white blood cells called leukocytes to activate, helping the tissue break down (4). Then the period occurs.
When your body releases these prostaglandins, stimulating your uterus to contract, your endometrial lining is released from your uterus. These prostaglandins, combined with a sharp drop in the ovarian hormones estrogen and progesterone, are believed to be responsible for gastrointestinal changes prior to and during menstruation (6). This is believed to be because prostaglandins may also act on the nearby intestinal tissue, causing inflammation (6).
Not everyone may notice this shift in stool patterns. One study found that around 50% of people with IBS or other bowel disorders experience a change in bowel habits around the time of their period. In comparison, only a third of women without bowel disorders experienced a bowel change related to menstruation (7). This means that not everybody experiences diarrhea or other gastrointestinal discomfort during their periods. If a person already lives with bowel discomforts, they may be more likely to have changes in bowel habits around menstruation (3, 7).
You might prevent premenstrual bloating and period diarrhea by avoiding certain foods
There isn’t a lot of research on how to treat the specific type of stomach complaints that accompany menstruation. As a rule of thumb, when you have diarrhea, it’s good to drink a lot of liquids to replace the ones you lose through your stool (8). Drinking and eating salt might help, so you can try soups, plain crackers, or sports drinks (8). Avoid dairy products, soda, and juice, along with anything that normally upsets your stomach (8). If your period diarrhea or other gastrointestinal changes last for longer than a couple of days, check in with your healthcare provider (8).
If you struggle with monthly digestive issues around the time of your period, one option is to talk to your healthcare provider about starting a form of contraception that can help you skip your periods, like oral contraceptive pills, the IUD, the shot, or the implant.
Tracking digestion throughout your cycle
Tracking your digestion can help you to keep an overview of your gastrointestinal experiences throughout your cycle—you can use Clue app daily for that. Reporting your experiences and discomforts to your healthcare provider from memory often does not end up reflecting the true condition of your health. Tracking your diet and experiences daily and over a longer period of time helps you and your healthcare provider analyze patterns. When does your stool change or when is your abdominal pain worse? Is there a relationship between your menstrual cycle, levels of stress, and eating habits?
Since every person is different, tracking is essential to get the best insight into your specific patterns.
When you better understand your individual patterns, you can anticipate when during your cycle you can expect diarrhea or abdominal pain, and take steps to ease your discomfort.
If you continue tracking while adjusting your eating habits or physical activity, you’ll get immediate feedback as to whether these changes actually improve your period experiences.
