How do your toilet habits change from week to week in your cycle?

My Hormonology

How do your toilet habits change from week to week in your cycle?



  • Where you are in your menstrual cycle impacts your bowel movements and how frequently you urinate, research shows.

UPDATED AUGUST 17, 2021 (originally published July 29, 2017)—Chances are, you’ve noticed that on some days, you have hard stool or are constipated for no apparent reason. Yet, on other days, your stool is loose or you have diarrhea–again for no apparent reason.

You’ve probably also noticed that on some days, you need to urinate more frequently, maybe heading to the bathroom twice as often during the day as you usually do. Or maybe you’re waking up two, three or even four times at night to empty your bladder. But, on other days, you could chug a gallon of water and hold it in for hours. And, again, there’s no obvious reason why.

Well, the inexplicable changes you experience in your bathroom habits may linked to where you are in your menstrual cycle.

Research shows that you can experience two distinct shifts in bowel movements and how frequently you urinate at certain points in your cycle. Read on to get a quick overview so you know what you can expect….


My Hormonology

Week 1: Flowing out

You’ve probably remarked on the strange coincidence that at the same time your body is expelling blood during your period, it’s also decided to open all the floodgates and completely empty your bowels and bladder. Truth is, these events are connected.

Numerous studies show that during the first few days of your period, you’re prone to getting loose stool or diarrhea.1

Researchers speculate it may be due to a build-up of prostaglandins–hormone-like chemicals that help expel the uterine lining during menstruation by stimulating contractions (the cause of menstrual cramps).2 These prostaglandins may enter the bloodstream, then make it to the intestines where they expel waste.

And there’s probably a lot of waste to expel due to constipation–or at least slower emptying–caused by progesterone in the second half of your cycle (see below).

You also tend to urinate more frequently during your period. This is likely due to a drop in progesterone, which had caused water retention during your Week 3 and most of your Week 4 (see below). Without progesterone holding in all that fluid anymore, you’re passing it more easily as you urinate.

Despite the more frequent trips to the bathroom, you might actually enjoy getting rid of the excess heaviness in your gut, feeling lighter and cleaned-out. Or you may see the constant interruptions in your day as an annoyance that pulls you away from your work, movie, book or hobby at the most critical moments. This is definitely one of those “Do you see the toilet half-full or half-empty?” kind of situations.

If diarrhea is severe or bothering you, you can try a natural approach to slowing things down: Ask your healthcare provider if it’s okay for you take 500 mg. of calcium twice daily. This mineral is known for stiffening stools by soaking up excess fluid that’s making everything so loosey-goosey.

Week 3 and Week 4: Staying in

Progesterone is higher during your Week 3 and Week 4, which is the second half of your menstrual cycle spanning the day after ovulation through the day before your next period. This is important to know because elevated progesterone prompts two key changes in bathroom behavior: It makes it more difficult for you to move your bowels by triggering hard stools or constipation.3 It also prompts water retention, leading to bloating and possibly fewer trips to empty your bladder than you experienced in your Week 1 and Week 2, the first half of your menstrual cycle.

Depending on your personal sensitivity to progesterone, these hormone-fueled bathroom effects may last all the way through the day you get your period or they may lighten up a few days before your period starts, unleashing softer stools and spurring more frequent bathroom trips to empty your bladder.

So, why is progesterone being so greedy with your food and beverages, not allowing them to easily pass through in this phase of your cycle?

Researchers suspect that this hormone wants your body to hold onto whatever you ingest longer as a way to sap more nutrients from them in case you got pregnant during ovulation and now need nutrients for two.

If constipation is bothering you, try eating more fiber-rich foods (such as legumes, whole grains, fruits and vegetables) along with drinking more water. Fiber and water work hand-in-hand to move stool. Plus, there are two study-backed natural treatments to try before resorting to drugstore laxatives:

  • Rye bread: In a 2010 study in the Journal of Nutrition, researchers found that whole grain rye bread works more effectively than laxatives and probiotics at relieving constipation.4 Credit goes to a type of fiber in rye bread–arabinoxylan–that ferments in the intestine and triggers contractions that move contents along. What’s more, it does the job without cramping or other uncomfortable side effects.
  • Prunes: A 2011 study from the University of Iowa Carver College of Medicine shows that prunes (now called by the less geriatric-sounding moniker “dried plums”) work more effectively than psyllium-containing fiber additives (like Metamucil and Fiberall) at making you regular again.5 That’s because they’re a rich source of sorbitol, a natural sugar alcohol that has a mild stool-softening effect.


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(1) Kotaro Maeda, et al., “Questionnaire Survey of Bowel Habit in Japanese Medical Personnel”, Journal of the Anus, Rectum and Colon, 5 (2021): 297-305
Matthew T. Bernstein, et al., “Gastrointestinal symptoms before and during menses in healthy women,” BMC Women’s Health, published online January 22, 2014
Aykut Ferhat Çelik, et al., “How prevalent are alterations in bowel habits during menses?” Diseases of the Colon & Rectum, 44 (2001): 300-301
(2) C. Arthur, Marvin E. Ement, Moon K. Song, “Prostaglandin metabolism in relation to the bowel habits of women,” Prostaglandins, Leukotrienes and Essential Fatty Acids, 46 (1992): 257-259
Margaret M. Heitkemper, Joan Shaver, Ellen Sullivan Mitchell, “Gastrointestinal Symptoms and Bowel Patterns Across the Menstrual Cycle in Dysmenorrhea,” Nursing Research, 37 (1988): 108-113
Monica Jarrett, et al., “Relationship between gastrointestinal and dysmenorrheic symptoms at menses,” Research in Nursing & Health, 19 (1996): 45-51
(3) Hye-Kyung Jung, Doe-Young Kim, Il-Hwan Moon, “Effects of Gender and Menstrual Cycle on Colonic Transit Time in Healthy Subjects,” Korean Journal of Internal Medicine, 18 (2003): 181-186
Michael I. McBurney, “Starch malabsorption and stool excretion are influenced by the menstrual cycle in women consuming low-fibre Western diets,” Scandinavian Journal of Gastroenterology, 26 (1991): 880-886
Arnold Wald, et al., “Gastrointestinal transit: the effect of the menstrual cycle,” Gastroenterology, 80 (1981): 1497-1500
(4) Reetta Holma, et al., “Constipation Is Relieved More by Rye Bread Than Wheat Bread or Laxatives without Increased Adverse Gastrointestinal Effects”, The Journal of Nutrition, 140 (2010): 534–541
(5) Ashok Attaluri, et al., “Randomised clinical trial: dried plums (prunes) vs. psyllium for constipation”, Alimentary Pharmacology & Therapeutics, 33 (2011): 822-828


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