The Truth About Period Poops: What’s Happening & Why

Oh my word...

This is the only phrase that comes to mind on day 2 of my period. Disclaimer – I’m about to be honest. Dealing with both the heaviest day of bleeding and diarrhea SUCKS. Here I am, at work, trying to use the bathroom before my next patient comes in quickly, and I must manage both my bleeding and suddenly having a bowel movement after several days of struggling. Why is this all happening at once, and when will it stop?? UGH.

I first learned that “period poops” had a physiological reason when I read Alissa Vitti’s book In the Flo several years ago. Through conversations with friends and patients, I soon realized that, yes, indeed, “period pooping” is a real thing that many menstruating humans experience.

Why does this happen?

Throughout our cycle, hormone shifts influence our bowel movements. In the luteal phase (right before menstruation), increased estrogen and progesterone cause a decrease in gastrointestinal motility (1). This means food moves slower through our intestines. Additionally, increased liquid absorption from stools contributes to constipation before our period. Research has shown that functional constipation is most common in women between the ages of 30-50, when estrogen still plays a role in bowel motility (1).

When we start our period, during the menstrual phase, progesterone and estrogen levels drop, and we experience a sudden increase in prostaglandins (2). Prostaglandins are responsible for:

• Dilating and constricting blood vessels

• Regulating inflammation

• Contracting the uterus by activating smooth muscle cells

Since the uterus and bowels are anatomically close and both contain smooth muscle, increased prostaglandins can cause bowel contractions, leading to diarrhea. After being constipated before our period, this sudden shift in motility can feel like a shock to the system.

For those who have given birth, you might recall experiencing a bowel movement during labor and delivery (3). That’s because the same prostaglandins that promote uterine contractions for labor can also increase bowel motility, leading to bowel movements during or after childbirth

Can I stop this from happening?

Prostaglandins are part of the body’s natural inflammatory process. While short-term inflammation is necessary for healing, chronic inflammation—due to diet, lack of exercise, or stress—can elevate prostaglandins, worsening “period poops” and menstrual cramping. Here’s how to help:

• Balance your omegas: Omega-6 can increase pro-inflammatory prostaglandins. Foods like vegetable oils, hydrogenated oils, and grain-fed livestock products are high in omega-6. Instead, opt for omega-3-rich foods like fish, nuts, seeds, and green vegetables (4). An omega-3 supplement may also help.

• Magnesium supplementation: Taking magnesium citrate or oxide around ovulation may help regulate bowel movements and ease constipation. However, if you already experience loose stools, be cautious with magnesium supplementation, as it can further increase bowel motility.

• Stay hydrated: Drink at least half your body weight in ounces of water daily. This is especially helpful before your period when stools lose more liquid, preventing constipation.

• Maintain fiber intake: Hormonal changes in the luteal phase may trigger cravings for sugary, fatty foods, which can worsen constipation and elevate blood sugar, increasing inflammation. Increasing fiber intake helps regulate bowel movements, reduce cravings, and improve digestion. Side note: If you’re not currently eating a high-fiber diet, gradually increase your intake to avoid sudden changes in bowel motility.

• Try a bowel massage: This can reduce abdominal discomfort, stimulate bowel movements, and ease bloating.

• Use a Squatty Potty: This helps optimize pelvic floor muscle length during bowel movements, easing constipation.

Thanks for popping a squat and talking about period poops with us!

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1. Otani, K., Watanabe, T., Takahashi, K., Nadatani, Y., Fukunaga, S., Hosomi, S., Tanaka, F., Kamata, N., Taira, K., Nagami, Y., Kimura, T., Fukumoto, S., Kawada, N., & Fujiwara, Y. (2021). Prevalence and risk factors of functional constipation in the Rome IV criteria during a medical check-up in Japan. Journal of Gastroenterology and Hepatology, 36(8), 2157–2164. https://doi.org/10.1111/jgh.15436
2. Judkins, T. C., Dennis-Wall, J. C., Sims, S. M., Colee, J., & Langkamp-Henken, B. (2020). Stool frequency and form and gastrointestinal symptoms differ by day of the menstrual cycle in healthy adult women taking oral contraceptives: a prospective observational study. BMC Women’s Health, 20(1), 136. https://doi.org/10.1186/s12905-020-01000-x
3. Brighten, J. (2018, June 22). How prostaglandins cause painful periods + what to do about it. Dr. Jolene Brighten. https://drbrighten.com/how-prostaglandins-cause-painful-periods-what-to-do-about-it/
4. Mariamenatu, A. H., & Abdu, E. M. (2021). Overconsumption of Omega-6 polyunsaturated fatty acids (PUFAs) versus deficiency of Omega-3 PUFAs in modern-day diets: The disturbing factor for their “balanced antagonistic metabolic functions” in the human body. Journal of Lipids, 2021, 8848161. https://doi.org/10.1155/2021/8848161