If you have IBS and periods you’ve probably experienced changes in your bowel habits through the menstrual cycle. You might be wondering whether you can do anything about worsening of IBS around your period so in this post I’m explaining why we get period poos, why you may get constipated before your period, and what you can do about it. 

Symptoms of can IBS worsen during your period

Female sex hormones have a wide range of actions, not just preparing the body for a pregnancy. So it makes sense that fluctuations in oestrogen, progesterone and testosterone will affect processes like the digestion, as well as mood, skin, and energy.

There are cell receptors for oestrogen and progesterone in the gut, not just in the relevant sex organs.

We know that almost twice as many women experience IBS as men, possibly down to the effect of sex hormones. Women with IBS are twice as likely to experience premenstrual anxiety and painful periods. 

During the perimenopause women may often experience worsening symptoms. This could be down to fluctuating hormones. 

close up of a woman's torso sitting on the edge of a bed, wearing a white t-shirt, clutching her stomach.

How your period affects IBS

Throughout the menstrual cycle you could notice changes like:

  • Increased sensitivity of the bowel –  researchers found rectal sensitivity increased for women with IBS around their bleed, when compared to women without IBS. 
  • You may experience a slowing of digestion in the run up the period
  • Many women get a day or two of loose stools when their bleeding starts. 
  • The rate of stomach emptying is likely to change, with the gastric emptying time 28 minutes faster during the luteal phase (second half of the cycle) compared to the follicular phase (first half). 
  • Hunger hormones change throughout your cycle as well – you may feel more hunger before your period, with a rise in progesterone. 


IBS constipation around period

Before your period starts there is a build up of hormones preparing your body for a baby. This slows down digestion in order to allow for proper nutrient absorption. 

It’s been shown in studies that stool consistency is firmer before your period and you might have a longer transit time.


Woman wearing a white vest and shorts sitting on the floor, arms around her knees, a red veil floating behind her.

IBS period diarrhoea

Have you ever experienced more urgency on Day 1 of your period? This could be a need to rush to the loo, and loose possibly smellier bowel movements that coincides with starting to get your period. 

When you get your period the release of blood is helped by prostaglandins. These are like local hormones which help the womb contract to release the lining of blood that has built up. They are also known to increase pain sensitivity, and may also encourage the bowel to contract and speed up. Nice. 

Could your gut bacteria affect your periods?

Microbes in your digestive tract can interact with sex hormones, and if these are out of balance they could increase your pre-menstrual symptoms. The bacteria which affect oestrogen are called the estrobolome. 

These bacteria produce beta-glucoronidase which can reduce the detoxification of oestrogen from the gut. Normally, to get rid of oestrogen we no longer need our liver cuts up oestrogen moelecules and makes them water soluble to be excereted in wee or poo. 

But beta-glucoronidase unhooks oestrogen from it’s water soluble transporter, so it can be reabsorbed into the body.  Increased abundance of β-glucuronidase-producing bacteria can lead to elevated levels of circulating estrogens.

If you have excess oestrogen you might find you get more PMS symptoms such as sore breasts, premenstrual acne, mood changes and sleeplessness.  


How to help your IBS during your period

Here are my hot tips for better digestive health during your periods.

  • Tracking – If you’re not already doing this then track your digestive symptoms against your cycle. Understanding your particular patterns is the most helpful thing you can do. Start today. 
  • In the pre-menstrual phase – increase your hydration and fibre. This will help to minimize constipation and keep bowels regular. 
  • A high fibre diet has been shown to reduce levels of beta-glucoronidase (the enzyme which may add to increased circulating levels of oestrogen). Aim for 30g fibre a day, with lots of diversity. 
  • Eating tofu, berries, citrus fruits and green leafy veg like spinach – this can help by encouraging beneficial gut bacteria, and adding polyphenols from the plants to help support healthy hormone levels.
  • During your period – avoid gut stimulants like alcohol or caffeine which can increase loose stools. You may find it helpful to reduce high FODMAP foods for a few days as well, including things like avocado, cauliflower, apples, or lentils. For more on the low FODMAP diet see my Beginners Guide to the low FODMAP
  • General tips for better periods include prioritizing your sleep and rest, particularly during the pre-menstrual phase.
  • You might not feel much like exercising just before or during your period, but some gentle movement like yoga or walking outside can do wonders for your mood, support better digestion, and help encourage better sleep.
  • check out tips for managing an IBS flare up to get more ideas on calming your IBS attack

If you’re looking for help with your digestion please get in touch via my Contact page or email info@goodnessme-nutrition.com

Hi I'm Anna Mapson, registered Nutritional Therapist.

I help people with IBS and SIBO get control of unpredictable gut symptoms to find long term relief from painful and embarrassing IBS without restrictive dieting.

I can help you to:

  • understand your digestion better, so you recognise your triggers
  • eat a well balanced diet, with tasty meals that are simple to prepare
  • develop better digestion and more energy

Find more about my 3 month 1:1 Gut Reset programme

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