# Gut feelings: bloating and period poos

> Why your tummy changes across your cycle

Category: Nutrition · 3 min read · Written by the Splash team · Sources checked October 2026
URL: https://splash.care/learn/nutrition/gut-bloating

## Quick answer

- Bloating before your period and looser poos during it are common.
- Smaller meals, movement, water and spotting your triggers help many people.
- Bloating that does not go away, or comes with warning signs, needs a GP check.

[Bloated](https://splash.care/learn/body-literacy/bloating) jeans before your period, then dashing to the loo on day one? Totally normal. In one study of 156 healthy women, almost three in four had at least one tummy symptom, such as pain, diarrhoea or constipation, in the days before or during their period.

## What is going on

The NHS says some people feel bloated around the time of their period. The most common reason for bloating is gas in the gut. Once your period starts, [Prostaglandins](https://splash.care/learn/glossary/prostaglandins), the chemicals that make your womb contract, are thought to affect the bowel too, which may be why looser poos are common in the first days.

## Things that may help

- Eat smaller, regular meals and chew with your mouth closed, to swallow less air.
- Move your body. The NHS says [exercise](https://splash.care/learn/period-care/exercise-on-period) helps digestion and can help when you are already bloated.
- Drink plenty of water, and go easy on fizzy drinks.
- If constipation is part of it, foods with soluble [fibre](https://splash.care/learn/glossary/fibre) like oats and linseed can help. Build fibre up slowly.
- Gently massage your tummy from right to left to release trapped wind.
- Notice your personal triggers. The NHS mentions some vegetables, beans, lentils, fizzy drinks, [alcohol](https://splash.care/learn/nutrition/caffeine-alcohol) and caffeine, but triggers differ for everyone.
- A pharmacist can suggest treatments like simeticone for bloating, or something for constipation.

> **Splash says:** log bloating and poo changes in the app. If they track tightly with your cycle, that is useful information to share with a doctor.

**Myth:** Bloating means you have gained weight.

**Fact:** Period bloating is mostly gas and fluid, and it often settles once your period gets going.

### When to see a doctor

See a GP if you are bloated often or it does not go away, or if bloating comes with weight loss you cannot explain, blood in your poo, or a lump in your tummy. Also tell a GP if you often have bloating, tummy or pelvic pain, feeling full quickly, or needing to pee more, roughly 12 or more times a month. These are usually caused by other things, but need checking. Ask for an urgent appointment or call 111 if bloating comes with being sick, a fever, or you cannot pee, poo or fart. Call 999 if you have a swollen stomach with severe pain that came on suddenly.

> If bowel symptoms are bad with every period, mention it. [IBS](https://splash.care/learn/glossary/ibs) and endometriosis can both be involved, and a symptom log makes that conversation easier.

## Sources

1. [NHS: Bloating](https://www.nhs.uk/symptoms/bloating/)
2. [Bernstein et al. (2014) Gastrointestinal symptoms before and during menses in healthy women, BMC Women's Health](https://pmc.ncbi.nlm.nih.gov/articles/PMC3901893/)
3. [NHS: Irritable bowel syndrome (IBS)](https://www.nhs.uk/conditions/irritable-bowel-syndrome-ibs/)
4. [NHS: Ovarian cancer, symptoms](https://www.nhs.uk/conditions/ovarian-cancer/symptoms/)
5. [NHS: Period pain](https://www.nhs.uk/symptoms/period-pain/)
6. [NHS: How to get more fibre into your diet](https://www.nhs.uk/live-well/eat-well/digestive-health/how-to-get-more-fibre-into-your-diet/)

This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).