The Science Behind Period Poo

Category: Health & Digestive Symptoms
Estimated read time: 3–4 minutes

Original sources

• Period Poop guide — Healthline
  👉 https://www.healthline.com/health/period-poop Healthline

• Gastrointestinal symptoms and the menstrual cycle — PubMed Central
  👉 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7768094/ PMC

• IBS & the menstrual cycle background (general research)
  👉 https://www.healthline.com/health/ibs-and-period

What period poops really are

“Period poops” is a colloquial name for the bowel changes many people notice just before or during their period, such as:

• Diarrhoea or more frequent bowel movements

• Constipation

• Changes in stool smell or texture

• Bloating and gas

These symptoms are linked to hormonal shifts in your menstrual cycle and are surprisingly common.

How hormones affect digestion

Your menstrual cycle involves regular rises and falls in hormones like estrogen, progesterone and prostaglandins, and these hormones don’t just affect your reproductive organs; they also influence your digestive system:

• Prostaglandins help the uterus contract to shed its lining, but they can also stimulate the smooth muscles of the intestines. This can speed up bowel movements and lead to diarrhoea during your period.

• Progesterone generally slows smooth muscle movement, which can lead to constipation, especially in the days just before your period

• Estrogen can affect gut sensitivity and motility as its levels change across the cycle.

Because these hormones are rising and falling at different times, it’s normal to experience both constipation and diarrhoea across your cycle — sometimes even in the same period

How your gut responds to your cycle

Research shows that bowel habits often change around menstruation:

• A significant portion of people notice changes in frequency or consistency during their period.

• Those with digestive conditions like Irritable Bowel Syndrome (IBS) often experience worse symptoms during menstruation, including diarrhoea, bloating, pain and constipation.

• Hormones have receptors throughout the digestive tract, meaning changes in estrogen and progesterone can directly affect gut function.

Why some people are more affected

If you already have a digestive condition such as IBS or Inflammatory Bowel Disease (IBD), you’re more likely to notice significant period-related changes in your bowel habits. Hormonal shifts can amplify symptoms like abdominal pain, urgency to poop, or alternating constipation and diarrhoea.

What this means for you

Period poops are real and normal. They’re usually part of how your body responds to hormones shifting throughout your cycle, particularly prostaglandins and progesterone. But that doesn’t mean there’s nothing you can do to feel better.

Here are practical tips that many people find helpful:

• Hydrate well — water supports overall digestion.

• Eat fibre-rich foods — fruits, vegetables and whole grains help regulate bowel movements.

• Stay active — gentle movement can reduce bloating and support gut motility.

• Pay attention to patterns — tracking bowel habits in your cycle can help you predict and prepare for “period poop days.”

If symptoms are severe, persistent, painful, or include bleeding or weight loss, that could signal a medical condition such as IBD, endometriosis or another digestive issue, and it’s worth discussing with a healthcare provider.

SHE takeaway:
Changes in bowel habits around your period, from diarrhoea to constipation, are very common and mainly driven by hormone-related effects on your digestive system. Understanding this can help you prepare, manage symptoms and make informed choices about lifestyle or medical support.

Medical Disclaimer:
This article is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare professional with concerns about your health.