Period-related GI symptoms are common enough to have their own moniker. The science, however, has barely kept up. Composite: The Guardian/Getty Images View image in fullscreen Period-related GI symptoms are common enough to have their own moniker. The science, however, has barely kept up. Composite: The Guardian/Getty Images Call the doctor Well actually The monthly scourge of ‘period poop’ is real. Here’s why your gut acts up Menstrual and digestive discomfort often coincide, and a researcher who has been looking in to it for a decade tells us what she learned
Prefer the Guardian on Google Every period, right on schedule: the cramps arrive, and right behind them, the urgent need to poop.
If this is your experience, you’re in good company: in one study, 73% of healthy premenopausal women reported at least one significant gastrointestinal symptom in the days before or during their period. Abdominal pain and diarrhea were the most common complaints, but women reported nausea and constipation too.
Menstrual and digestive discomfort often coincide: “If you ask women about ‘period poops’ they’ll tell you they’re having menstrual cramps and those GI cramps at the same time,” said Taylor Judkins, a nutrition researcher at the University of Florida who has spent more than a decade studying the phenomenon.
Period-related GI symptoms are common enough to have their own moniker. The science, however, has barely kept up. Judkins has personal experience with the phenomenon; when she first went looking for research on the phenomenon as a university student, she found almost nothing. A decade later, she says, there’s still a lot to learn.
It all starts with the uterus. As your period approaches, levels of estrogen and progesterone fall sharply. That’s the signal for your body to start breaking down the uterine lining, which you start shedding on day one of your period.
At the same time, cells in the uterus start making hormone-like compounds called prostaglandins. These cause contractions in the type of muscle cells that make up most of your uterus and digestive tract, among other effects.
It’s unclear exactly what happens next. But the leading theory, said Judkins, is that some prostaglandins enter the bloodstream from the uterus and stimulate similar contractions in the neighboring gut. This would explain the intestinal cramping and diarrhea many experience alongside menstrual cramping, especially on the first day or two of their periods.
One other theory relates to the vagus nerve, which runs signals between the gut and the brain. This neural pathway is highly sensitive to stress signals and inflammation. When activated, it provokes fluid release within the gut and increased contractions of its muscles, leading to diarrhea. This is why some experts believe many people get an upset stomach when they’re anxious. Judkins theorizes that menstruation may also trigger the pathway.
Many women also note constipation one to two weeks before their periods start, says Judkins, which may be a consequence of high progesterone levels. However, the evidence is less clear on the prevalence and timing of that symptom.
People with irritable bowel syndrome and inflammatory bowel disease tend to have significantly worse symptoms around their periods, and those with endometriosis typically carry a higher burden of GI symptoms overall. But you don’t need an underlying diagnosis to have period poops.
“It’s very common, and some will tell you that it’s normal,”…