As if the mood swings, cramps, and cravings didn’t make that time of the month your least favourite time, there’s a good chance your cycle can also wreak havoc on your bathroom routine. Here’s exactly what happens to your tummy when you’ve got your period—and how to get sh*t under control—literally.

During the first few days of your period, your body releases prostaglandins. Prostaglandins are compounds that have a ton of complex roles, including triggering the uterus to contract. Unfortunately, these prostaglandins don’t just stay in the uterus, they circulate around the whole area. That area included your bowels, prompting them to contract and – you guessed it – you go to the bathroom more. But not everyone experiences this. When women poop more during their cycle, it’s often due to an excess of prostaglandins; if you tend to get stopped up, it can be because your body makes fewer prostaglandins.

What does it feel like?

Looser stools than normal, having to go to the bathroom more often, and feeling more urgency—like, I gotta go now—are all very common side effects of a sharp rise in prostaglandins. We also release prostaglandins around ovulation, which may be why you get that same affect halfway through your cycle.

If you’re finding, though, that if your bowels are typically screwy—and get even screwier when you have your period—it could point to a bigger problem – IBS. About 12 percent of the population has irritable bowel syndrome [IBS], a condition where you might have alternating constipation and diarrhea—and IBS symptoms can get worse when you menstruate. So if that’s going on, make sure you talk to a medical provider about it.