People may experience a range of symptoms before and during menstruation. Diarrhea is a symptom people often experience during their period, likely due to an increase in the production of prostaglandins in the body.

Here, we look at why having a period can cause diarrhea and other gastrointestinal issues. We also provide tips on how to ease painful symptoms, and when to see a doctor or other healthcare professional.

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An increase in the production of prostaglandins in the body during a period may cause diarrhea.

Some people may experience diarrhea during or before their period. This is likely due to an increase in the production of prostaglandins in the body.

Prostaglandins are hormone-like chemicals that assist certain functions in the body, including:

  • muscle contractions
  • blood vessel dilation and constriction
  • blood clotting

Before a period starts, cells in the lining of the uterus increase production of prostaglandins. This increase in prostaglandins causes the uterus muscles to contract, thereby releasing the lining of the uterus. This is what a female experiences as her period.

The more prostaglandins the body makes during menstruation, the more the uterus will contract. As such, excess production of prostaglandins can cause menstrual cramps and pain.

When prostaglandin levels are high, some prostaglandins may enter the bloodstream. They can then travel to various parts of the body, including the bowels.

The bowels have a smooth lining of muscle, similar to the uterus. High levels of prostaglandins can cause the bowels to contract and release their contents, resulting in diarrhea.

Excess prostaglandins can also cause other period-related symptoms, including:

Apart from causing pain and discomfort, excessive amounts of prostaglandins do not cause any health risks.

Changes in prostaglandin levels can also cause other gastrointestinal (GI) symptoms during a period.

A 2014 study of healthy premenopausal women investigated the GI and emotional symptoms some people experience before and during their period.

Of the 156 participants, 73% experienced at least one GI symptom before or during a period. Abdominal pain and diarrhea were the most common. Participants also experienced:

Women who experienced emotional symptoms, such as depression or anxiety, were more likely to report multiple GI symptoms.

A 2013 study compared premenstrual GI symptoms in people with and without inflammatory bowel disease (IBD). The researchers found that people with IBD experienced more frequent premenstrual GI symptoms. However, their IBD symptoms did not change significantly over the course of the menstrual cycle.

In contrast, people with irritable bowel syndrome (IBS) may experience a worsening of bloating, abdominal pain, and other IBS symptoms during their period, according to an article in Gastroenterology Report.

Endometriosis is where tissue similar to the lining of the uterus grows outside the uterus. Endometriosis can occur in the following areas:

  • ovaries
  • fallopian tubes
  • area around the uterus
  • vagina
  • cervix
  • bladder
  • bowel
  • rectum

According to the Endometriosis Foundation of America, GI symptoms are a very common feature of endometriosis. The symptoms typically worsen during menstruation, and may include:

Other symptoms of endometriosis include:

  • painful menstrual cramping
  • persistent pain in the lower back and pelvis
  • stomach or intestinal pain
  • pain during bowel movements or urination during a period
  • blood in stools or urine
  • deep-feeling pain during or after sex
  • bleeding or spotting in between periods
  • infertility

If people suspect endometriosis is causing diarrhea and other menstrual symptoms, they should see their doctor for a diagnosis.

People can take steps to treat diarrhea and other menstrual symptoms at home. We outline some tips below.

Treating diarrhea

Some general tips for easing diarrhea include:

  • Drinking plenty of fluids: This is important for preventing dehydration. People should drink throughout the day, and should drink an extra cup of water after each bout of diarrhea.
  • Consuming a liquid diet: This helps to rest the bowels. People can try drinking weak tea, apple juice, or clear broth.
  • Eating smaller meals more frequently: This can make food easier for the body to digest.
  • Eating foods high in pectin: Pectin is a water-soluble fiber that can help to reduce diarrhea. Foods that are high in pectin include applesauce, bananas, and yogurt.
  • Replacing electrolytes: Diarrhea can deplete levels of potassium and other electrolytes in the body. People can replace electrolytes by drinking sports drinks, fruit juices, or coconut water. Good food sources of potassium include bananas, and potatoes with the skin.
  • Eating salty foods: Salty foods, such as crackers, pretzels, and soups, help to replace lost sodium. This, in turn, helps the body retain more water.

People should also avoid foods and drinks that can irritate the digestive tract and worsen diarrhea. Examples include:

  • caffeine
  • alcohol
  • carbonated drinks
  • foods that are very hot or very cold
  • high-fat, greasy foods
  • milk products
  • tobacco
  • marijuana

Treating other menstrual symptoms

Below are several dietary and lifestyle tips that could help to alleviate GI symptoms and other menstrual symptoms.

  • Exercising regularly: Keep up regular exercise throughout the month, especially aerobic activity that raises the heart rate.
  • Avoiding certain ingredients: Avoiding foods and drinks that contain caffeine, salt, or sugar for 2 weeks before a period may help to reduce PMS symptoms.
  • Getting a good nights sleep: Ensure regular, good-quality sleep, and aim for 8 hours each night. This may help to alleviate mood-related menstrual symptoms.
  • Reducing stress and anxiety: Activities such as yoga, meditation, and journaling may help to ease stress-related GI symptoms.
  • Avoiding smoking: People should avoid smoking. According to the Office On Women’s Health, smoking may increase the severity and frequency of pre-menstrual symptoms. Learn more about quitting smoking here.

People should see their doctor if they experience any of the following:

  • diarrhea lasting more than 2 days
  • blood in the stools, which may indicate an infection or other underlying health condition
  • severe physical or psychological symptoms before or during periods, which may indicate an underlying health condition

People should also see a doctor or other healthcare professional if they think they may have endometriosis. The doctor will work to diagnose the condition and provide treatments to ease the symptoms and help prevent recurrent symptoms.

People may experience diarrhea and other GI issues before and during their period. This is usually due to an increase of prostaglandins, which can cause cramps, diarrhea, and other GI issues.

People who experience diarrhea during their period can follow standard guidelines for treating diarrhea. This includes drinking plenty of fluids, and replacing lost electrolytes.

Severe symptoms during or before a period can sometimes indicate an underlying health condition. People should take note of their symptoms, and schedule an appointment with their doctor or gynecologist.

These health professionals will work to diagnose the cause of the symptoms, and provide appropriate treatments.