Serious Question: Why Are My BMs Irregular During My Period?

period pain


We’ve all had that uneasy feeling during our period: maybe you’re at the movies, walking to work, or laying in your bed watching Netflix. You feel what initially reminds you of a period cramp, and then realize your body is signaling something entirely different, yet just as unpleasant. Friends, I’m talking about the dreaded and infamous period bowel movements, a mysterious phenomenon that tend to appear during your cramp-iest time of the month. 

What are period bowel movements, you may ask? These coincide with your period, and can often be irregular and uncomfortable. When you’re on your period, a natural chemical in your body called prostaglandins are produced inside your uterus, encouraging it to contract and shed its lining, which often results in you experiencing uncomfortable cramping and bloating. Prostaglandins also ignite contracting in your digestive tract, which can result in some bizarre bowel movements while you’re preparing or experiencing your period.

What Are Prostaglandins?

Prostaglandins are compounds in the body made of fats that have hormone-like effects and assist in regulating the reproductive system by helping to control ovulation.

If you find yourself rushing to use the bathroom more often when you're on your period, we have some ideas, along with Dr. Sara Twogood, a Los Angeles-based OBGYN, on how to get your body running smoothly again.  

Meet the Expert

Sara Twogood, MD is a board-certified obstetrician-gynecologist, working and living in Los Angeles for more than a decade. She did her internship and residency at Los Angeles County and University of Southern California and subsequently practiced medicine at Keck Medicine of USC while serving as an Assistant Professor of Obstetrics and Gynecology. She is a Los Angeles Magazine "Top Doctor" and has a passion for educating the public about female health and wellness.

If you're constipated on your period...

Maybe your digestive problem during your period is not being able to have a BM at all. If this is the case, reflect on what medications you might be using to combat your period cramps and other symptoms. "Pain medications that are commonly used for menstrual cramps, like ibuprofen, can also cause slight constipation," explains Twogood. "I recommend ibuprofen as first line pain medication, but increasing fiber and water intake while using ibuprofen may help with this unwanted side effect. Magnesium supplements can help with constipation, or using an over-the-counter stool softener is fine for occasional use as well.”

Constipation may also be caused by a change of diet and other lifestyle choices while you’re on your period. "Women often change their eating habits right around their period, like indulging in more sweets, white flour, or processed foods," Twogood explains. Rather than zip through the fast food drive-thru, Twogood recommends whole foods that are high in fiber, like fresh fruit, lentils, Brussels sprouts, and chickpeas. Popcorn is also high in fiber, and may be the perfect snack to satisfy your period cravings, too.

If you have diarrhea on your period...

Lifestyle choices are a key factor in experiencing diarrhea during your period, including your water intake, dietary preferences, and drinks of choice. "Make sure you stay well hydrated and avoid foods or supplements that can make stools loose, such as magnesium-rich foods or supplements," explains Twogood. Foods like avocados, beans, rice, and nuts contain a high volume of magnesium, and could be triggering while you’re on your period (AKA maybe skip the avocado toast at brunch and opt for poached eggs instead). Alcohol and caffeine can also prompt diarrhea, so avoid the Bloody Mary and cold brew and opt for tap water or seltzer—lots of it!

How to get things moving regularly

While period bowel movements can result in some unpleasant surprises, being thoughtful about your diet, fluid intake, and medication could make a world of difference. As soon as you begin to feel period symptoms, start drinking lots of water and try to keep up a consistent, healthy diet (not an easy feat, we know). Be mindful of the symptoms certain medications can cause, as ibuprofen, antihistamines, and over-the-counter sleeping pills can contribute to constipation and irritability. 

And, of course, don’t be afraid to ask for help. "If the irregular bowel symptoms persist beyond a week or two, or you're having severe pain or other very worrisome symptoms, check in with your primary care doctor," suggests Twogood. No matter what type of BMs you encounter on your period, we hope this helps pave the way toward a more regular future.

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