Most people are pretty open about the “joys” that come with having a period, like cramps, bloating, and sore boobs. But there’s one period side effect people really need to discuss more often, because maybe sharing the burden can at least make the load a little lighter: period poop.

Everyone’s situation is different, but it’s not uncommon for your regular poop habits to take a temporary vacation when you’re on your period, or be suddenly replaced with a whole lot of diarrhea, or both. “Many women do get bowel changes just before or during their period,” Kyle Staller, M.D., a gastroenterologist at Massachusetts General Hospital, tells SELF.

You’ve probably noticed this and dismissed it as just one of those body things, but there’s an actual biological cause you should know about.

“The reason that this happens is largely due to hormones,” says Dr. Staller. Pre-period constipation could be a result of an increase in the hormone progesterone, which starts to increase in the time between ovulation and when you get your period. Progesterone can cause food to move more slowly through your intestines, backing you up in the process.

So what about that diarrhea, though? Hormone-like substances called prostaglandins could be to blame for that. The cells that make up the lining of your uterus (known as endometrial cells), produce these prostaglandins, which get released as the lining of your uterus breaks down right before and during your period. If your body makes a lot of prostaglandins, they can make their way into the muscle that lines your bowels. There, they can cause your intestines to contract just like your uterus and push out fecal matter quickly, causing diarrhea in the process, Ashkan Farhadi, M.D., a gastroenterologist at MemorialCare Orange Coast Medical Center and director of MemorialCare Medical Group’s Digestive Disease Project in Fountain Valley, California, tells SELF. (Fun fact: These prostaglandins are also responsible for those painful cramps you might get every month.)

Of course, this can all vary in different people. But if you notice you experience constipation or diarrhea right around your period like clockwork, this may be why.

Having certain health conditions can also exacerbate period-related bowel changes.

If you struggle with a health condition like endometriosis, Crohn’s disease, irritable bowel syndrome, or ulcerative colitis, having your period can cause a flare-up of your symptoms. Ultimately, the symptoms you experience depend on your condition, Dr. Farhadi says.

For example, if you struggle with Crohn’s disease, which can often cause diarrhea, or IBS-D (a form of IBS that causes people to have diarrhea), your body’s release of prostaglandins during your period may cause you poop even more than usual. But if you suffer from IBS-C (IBS that causes people to have constipation), you may find yourself struggling even more to have a BM on your period as progesterone further slows your bowels’ activity. Since ulcerative colitis can lead to both diarrhea and constipation, you might experience an uptick in either during your period.

And unfortunately endometriosis can lead to pain during bowel movements around your period, Christine Greves, M.D., a board-certified ob/gyn at the Winnie Palmer Hospital for Women and Babies, tells SELF. Endometriosis is a disease where endometrial tissue that normally grows inside the uterus (or, as is up for debate, tissue similar to endometrial lining) grows outside of the uterus. This tissue can attach to your bowels and start trouble. “You then have bleeding around that area, and that can cause pain when you have a bowel movement,” Dr. Greves explains.

If your poop gets weird on your period, there are a few things you can do to cope.

The most important step is knowing what’s normal for you on your period and doing what you can to minimize any additional triggers. For instance, if you always get diarrhea during your period, and you know that coffee tends to make you poop more, it’s a good idea to cut back a little when you’re actually on your period, Dr. Farhadi says. You can also take Immodium on the first day of your period in anticipation of diarrhea, or carry it with you in case it strikes, he says. If you deal with constipation during your period, try upping your fiber and water intake in the middle of your cycle, when constipation-prompting progesterone levels start rising.

It can also help to pop some non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs, a common class of pain relievers, can block certain enzymes in your body from making prostaglandins. With fewer prostaglandins roaming around, you may get some relief from an achy belly and incessant pooping.

If you’re really having a hard time with poop issues on your period, talk to your doctor. They may be able to recommend next steps or refer you to a specialist who can. Your period is already annoying enough without spending forever on the toilet, either basically pooping water or straining hard to go in the first place.