Your Gut and Your Cycle: IBS and Digestive Changes in Women

TL;DR: Many women notice their gut changes around their period, with tummy pain, bloating and diarrhoea among the most common symptoms. IBS is about twice as common in women as in men and often flares around menstruation. NICE says your doctor should ask about weight loss you cannot explain, bleeding from your bottom, and a family history of bowel or ovarian cancer. Bowel pain that comes with your period can also be a sign of endometriosis, so track the pattern and tell your doctor.

You know the pattern even if nobody ever named it for you. A day or two before your period, your tummy swells so your jeans feel tight. Then day one arrives with cramps, and with them, urgent trips to the toilet. Some months it is constipation instead. You may have laughed about "period poops" with your sisters or friends, but quietly wondered whether it is normal, or whether something else is going on. The short answer: it is very common, and it is also worth paying attention to, because the gut and the cycle are closely linked, and a few patterns need a doctor.

Is it normal to have diarrhoea or bloating around your period?

Yes, for many women it is common. In a study of 156 healthy women attending a gynaecology clinic, 73% had at least one digestive symptom in the five days before or during their period. Abdominal pain was the most common, and around a quarter had diarrhoea before or during menstruation. Tiredness was also common and was linked with having several gut symptoms at once.

Why your gut follows your cycle

Your womb and your bowel sit close together in your pelvis, and they respond to some of the same chemical signals. A review of digestive symptoms across the menstrual cycle describes two things researchers have seen. First, food can move more slowly through the gut in the luteal phase, the second half of your cycle after ovulation, which may help explain the bloating and constipation some women feel in the days before a period. Second, the same review suggests that higher levels of prostaglandins during menstruation, the hormone-like chemicals involved in period cramps, may play a part in the pain, bloating and diarrhoea many women notice once bleeding starts.

If you already feel drained in the run-up to your period, the gut changes can stack on top of that. We go through the rest of that week in why you crash the week before your period.

What is IBS, and why is it more common in women?

Irritable bowel syndrome (IBS) is a common long-term condition that affects the digestive system. The NHS describes its main symptoms as stomach pain or cramps that usually get worse after eating and better after a poo, bloating, diarrhoea and constipation, with flare-ups that come and go. It can also cause tiredness, nausea, backache, pelvic pain and needing to pee often. The exact cause is unknown, but it has been linked to food moving through the gut too quickly or too slowly, a past stomach infection, an oversensitive gut, stress and a family history of IBS.

NICE, which writes clinical guidance for England, says IBS is twice as common in women as in men and most often affects people between 20 and 30. The US National Institute of Diabetes and Digestive and Kidney Diseases also notes that women are up to two times more likely than men to develop IBS. Researchers have found that women with IBS often report worse pain, bloating and diarrhoea during their period, and that their symptoms follow a cyclical pattern more closely than in women without IBS.

How IBS is diagnosed

There is no single test that confirms IBS. Instead, the NICE guidance for the public says your doctor should ask whether you have had tummy pain or discomfort, bloating, or a change in bowel habit for at least six months. A diagnosis is considered when the pain eases after a poo or comes with a change in how often you go or how your stool looks, alongside at least two other symptoms such as straining or urgency, bloating, symptoms that are worse after eating, or passing mucus.

NICE also says you should be offered blood tests to check for anaemia, inflammation and coeliac disease, a condition where gluten damages the gut lining. Scans and camera tests are not usually needed to confirm IBS if you meet the criteria and have no warning signs. If the doctor says "it is just IBS" without asking you any questions about your cycle, it is fair to bring it up yourself.

Red-flag symptoms: when to see a doctor quickly

NICE says that before IBS is diagnosed, your doctor should rule out conditions that need specialist care, including cancer and inflammatory bowel disease. According to the NICE public guidance, you should be asked about:

• Weight loss you did not intend and cannot explain
• Bleeding from your bottom
• A family history of bowel or ovarian cancer

The NHS also advises asking for an urgent GP appointment or contacting NHS 111 if you have lost a lot of weight for no reason, are bleeding from your bottom or have bloody diarrhoea, find a hard lump or swelling in your tummy, or feel short of breath with a racing heart and paler skin than usual.

Age matters too. The NICE suspected cancer guideline says that women aged 50 or over who have had IBS-like symptoms in the last 12 months should have tests for ovarian cancer, because IBS rarely starts for the first time at that age. If you are in your fifties and your gut has suddenly changed, do not let anyone, including yourself, wave it away as stress.

If you live in Nigeria, Ghana or Kenya and cannot easily see a gastroenterologist, a general doctor at your local hospital can still start these checks. Bring a written list of your symptoms and any family history you know.

When it might be endometriosis

Endometriosis is when tissue similar to the womb lining grows in other places, sometimes on or near the bowel. The NICE endometriosis guideline says doctors should suspect it in anyone with one or more of these: period-related or cyclical gut symptoms, especially painful bowel movements, period pain that disrupts daily life, chronic pelvic pain, or deep pain during or after sex.

The overlap with IBS is significant. A systematic review and meta-analysis found that women diagnosed with endometriosis were two to three times more likely to also meet the criteria for IBS. The authors note it is not always clear whether these are two separate conditions or whether endometriosis is producing IBS-like symptoms. Either way, the practical point is the same: if your gut symptoms clearly track your period, especially sharp pain when you open your bowels, say so, and ask whether endometriosis has been considered. We explain how to describe these symptoms in not just a bad period: signs of endometriosis, and the condition itself in endometriosis explained.

What can help day to day

For people diagnosed with IBS, the NHS suggests keeping a food and symptom diary, not skipping or delaying meals, eating slowly, drinking around 1.5 litres of fluid a day, keeping tea, coffee and other caffeinated drinks to three cups a day, and cutting back on fatty, spicy and processed foods. That last one can feel personal when pepper soup and a good stew are part of home. You do not have to give them up, but noticing whether a heavily spiced meal the day before your period sets you off is useful information.

For bloating, the NHS suggests eating oats regularly and up to a tablespoon of linseeds a day. For diarrhoea, it suggests cutting down on high-fibre foods like wholegrains, nuts and seeds, and avoiding the sweetener sorbitol. A pharmacist can talk you through options the NHS mentions, such as peppermint oil for cramps and bloating, loperamide for diarrhoea, or a laxative for constipation. See a GP if pharmacy medicines and diet changes are not helping, or if you are avoiding so many foods that eating has become stressful.

Track the pattern, then take it to your doctor

The single most useful thing you can bring to an appointment is a clear record. Note the day of your cycle, what your stool was like, any pain and how bad it was, bloating, and what you ate. After two or three cycles, a pattern often appears, or it does not, and both answers help your doctor.

This is where Asele fits in. You can log your cycle and symptoms, including bloating, gut changes and pain, so the pattern builds over time. Before an appointment, the Asele Health Brief turns that history into a summary you can take to your doctor. If you want to talk through what you are noticing first, Amara can chat with you in Yoruba, Hausa, Igbo, Swahili, French or English. You can find us at Asele.

This post is education, not medical advice. If you have any of the red-flag symptoms above, or your gut has changed and is not settling, see a doctor rather than waiting for it to pass. For other causes of pain low in your tummy, see our guide to pelvic pain.

References

1. Bernstein MT, et al. Gastrointestinal symptoms before and during menses in healthy women. BMC Women's Health, 2014. pubmed.ncbi.nlm.nih.gov
2. Bharadwaj S, et al. Symptomatology of irritable bowel syndrome and inflammatory bowel disease during the menstrual cycle. Gastroenterology Report, 2015. pubmed.ncbi.nlm.nih.gov
3. NHS. Symptoms of IBS. nhs.uk
4. NHS. What is IBS. nhs.uk
5. NHS. Diet, lifestyle and medicines for IBS. nhs.uk
6. NICE. Irritable bowel syndrome in adults: diagnosis and management (CG61), introduction. nice.org.uk
7. NICE. Diagnosing irritable bowel syndrome, information for the public (CG61). nice.org.uk
8. NICE. Suspected cancer: recognition and referral (NG12). nice.org.uk
9. NICE. Endometriosis: diagnosis and management (NG73). nice.org.uk
10. National Institute of Diabetes and Digestive and Kidney Diseases. Definition and facts for irritable bowel syndrome. niddk.nih.gov
11. Saidi K, Sharma S, Ohlsson B. A systematic review and meta-analysis of the associations between endometriosis and irritable bowel syndrome. European Journal of Obstetrics, Gynecology and Reproductive Biology, 2020. pubmed.ncbi.nlm.nih.gov