Why does my stomach get upset during my period?

Naturopath, Herbalist and Yoga teacher (BA, Dip Nat, Dip Herb)
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19 June 2021

Why does my stomach get upset during my period?

Many different things can contribute to an upset stomach during your period, often not-so-affectionately referred to as "period poop". Nausea, gas and bloating can also pop up during and before the period. There isn't a definitive answer as to what causes these digestive period problems, however hormones and diet both seem to play a role.

5 upset stomach causes during period

The female body is so complex and science only understands a small portion of what goes on in our bodies. (1

"Period poop" and "period farts" are common complaints I see with my clients. This usually presents along with other symptoms of PMS or with dysmenorrhea, aka painful periods. Bloating is also a common issue and I covered many remedies for bloating, as well as why it happens, in my blog "Why am I so bloated during my period?"

So, let's take a look at 5 potential causes that can contribute to digestive problems before and during menstruation. This list is not exhaustive but may give you an insight into the complexity of the issue.

It really is amazing how little we understand the mechanisms that go on in the female reproductive system. Considering that over half the world's population menstruate at some point in their life and considering that it is a process that literally gives life to all humankind! But that rant is for another day and another blog!

1. Prostaglandins

Many medical professionals think there may be a link with hormones called prostaglandins, which contribute to the cramps often associated with menstruation. They can also cause the intestines to contract, which leads to digestive complaints like nausea, bloating, gas, constipation and diarrhoea: the dreaded "period poop". (2)

These prostaglandins are actually a really helpful part of menstruation and we definitely need them! They help the uterus to contract so it can shed its lining, resulting in your monthly bleed. When out of balance, these prostaglandins can also contribute to digestive complaints as well as period pain. But, as a naturopath, I am always wondering what causes these prostaglandins to cause problems for some people but not others. So, I'm not sold on them being the main culprit! This is where diet could mingle in – a diet high in animal fats and proteins would contribute to higher levels of prostaglandins.

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2. Shifts in oestrogen and progesterone

Oestrogen and progesterone naturally rise and fall throughout our cycles. The rise in progesterone during the second half of our cycle is believed to cause our bowels to become more sluggish, contributing to constipation. There is, however, an emerging theory that oestrogen is actually the culprit. (3)

What we do know is that hormones likely play a role, and when the hormones are out of balance, these digestive symptoms can be worse.

3. Unhealthy diet

A diet high in sugar, salt, refined grains and too much processed foods can wreak havoc with our whole bodies! These foods themselves can often contribute to digestive complaints, and it might be that we just notice them more in the premenstrual phase. We are more sensitive to pain in general in the days before our period, so that may be one of the reasons why some women experience more digestive discomfort at this time too. (4)

A fall in magnesium in the pre-menstrual week makes us more sensitive to pain, as does a bad diet and, ironically, taking more painkillers!

A diet high in processed food also lacks fibre, which helps to keep our bowels moving. Fibre is also important food for our healthy gut bacteria. On the other hand, sugar is what the bad guys thrive on, so an unhealthy diet, lacking in whole fresh plant-based foods, can contribute to dysbiosis, an imbalance in the bacteria of our microbiome. A healthy microbiome is so important for so many aspects of our health and an imbalance of bacteria in our gut can contribute to digestive complaints. Certain healthy bacteria are also needed to metabolise our hormones, so it has a big role to play in all PMS symptoms, not just the digestive issues. As I said before it's all connected!

4. Gut-brain connection

The gut-brain connection refers to the link between our brains and our digestive systems. It is why when we are nervous or excited we get butterflies in our tummies! 90% of our serotonin, the happy hormone, is produced in our intestines, not our brains. Studies have found a link between depression and digestive complaints during menstruation (5) while another study asks whether the digestive complaints cause mood fluctuations or vice versa. (6)

5. Hormonal Birth Control

The use of oral contraceptives has been linked to inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. (7) If you are taking hormonal birth control it is worth considering that it may be contributing to digestive complaints before or during your bleed as well. You can discuss this, as well as potential alternative birth control methods, with your health care provider.

What helps an upset stomach during your period?

Many articles online and many doctors seem to recommend hormonal birth control for PMS symptoms, including digestive complaints. However, as a naturopath, I am generally opposed to using medications in this way.

Hormonal birth control is a wonderful resource for women who do not wish to get pregnant, and I am glad this option is available to us now. However, using these synthetic hormones to deal with symptoms caused by a deeper imbalance is what we would call suppressing the symptoms.

This can lead to more problems down the road, including a larger issue which is now being called Post Birth Control Syndrome and more severe menopausal symptoms. And as I mentioned above, the pill can contribute to digestive issues as well.

As a naturopath, I find that the most profound healing happens for people when they are ready to take control of their health and their lives and make the dietary and lifestyle changes needed.

These changes aren't always easy but they are oh so rewarding! If your symptoms are severe, or if the following ideas don't help, it is worth seeking out a naturopath or herbalist who can help you on your journey.

1. Drink herbal teas

Let's start with an easy one! Herbal teas are a delicious and comforting addition to your diet. Some that are particularly helpful are:

  • Ginger – great for nausea, bloating and any digestive pain or period pain.
  • Peppermint – brilliant for bloating and gas, and headaches.
  • Chamomile – anti-inflammatory, prebiotic, calming for the digestive tract and the nervous system, good for gas and bloating, and helps to balance hormones.

Wow, herbs are amazing!!

2. Reduce processed foods

Easier said than done in a society that promotes so much junk! The easiest way to do this I find is to add more healthy food in and make healthier choices one meal or snack at a time. More fruit and veg, less processed white stuff, one day at a time.

3. Eat a simple, warm, cooked foods

Traditional Chinese Medicine and Ayurveda, India's traditional medicine system, both recommend eating warm, cooked and easily digestible foods during your period, and the days before. Too much cold food is considered to contribute to pain and stagnation and should be avoided.

Soups and stews are a great option! Check out a recipe for the delicious Ayurvedic kitchari dish made with rice and lentils and healing spices. It is the perfect food for when you're menstruating and your tummy doesn't feel great.

4. Embrace the bitter taste

Most of us are really lacking the bitter taste from our diets. Bitter foods and herbs are a great way to kick start your digestion and help rebalance upset tummies. Dandelion greens, rocket and endives are a good way to incorporate these into your diet. You can also try some herbal bitters, like Yarrow, Gentian, or Digestisan drops, a mix of dandelion and artichoke. Just a few drops in some water before you eat can go a long way to easing gut discomfort.

5. Add 2 tbsp of flaxseed to your diet

Also known as linseeds, these incredible seeds are high in omega 3s, a rich source of hormone-balancing phytoestrogens and a bulking fibre high in mucilage which is great for digestion. A small sprinkling on your porridge isn't going to cut it though, go for 2 tablespoons daily to get the full benefit of these wonderful seeds.

6. Try some gentle movement

When you are menstruating and feeling queasy, you likely don't feel like exercising much. If that's the case it's good to listen to your body. Some gentle movement, like a walk in fresh air or some yoga, can help. Simply rotating your hips in a circular motion can feel really nourishing too. Here are some gentle yoga poses you can try:

Need help easing your pre-menstrual symptoms?

Agnus castus is often called the 'female herb' and with good reason! Not only can it help ease menstrual cramps, but it can also help relieve other common PMS symptoms, including bloating, mood swings, irritability and breast tenderness.

It is best suited to women experiencing these oestrogen dominance symptoms, as well heavy, painful periods, often arriving more frequently than every 28 days (such as 21-27 day cycles). Please note though, this herb is not suitable for anyone using hormonal contraception such as the Pill or Mirena Coil.

My Top Tip:Take Agnus castus on an ongoing basis, not just while you are menstruating


"Top-notch quality, this stuff is a life saver!" Larissa Matharu

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As the A.Vogel  Women’s Health advisor, I recommend Agnus castus to help relieve premenstrual symptoms such as painful periods.

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Did you know?

Did you know the average age of starting your periods has changed? A 100 years ago, 16 was the average age for a girl to get her first period in the UK but now this has dropped to just 12! Incredible!

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