2. Bowel Irritation
During menstruation, chemicals called prostaglandins are released into the uterus and the bowel. These prostaglandins cause the uterus to contract. The effect on the uterus is the well-known cramps women experience. But these chemicals also affect the bowel by causing the smooth muscles of the digestive tract and intestines to contract, which essentially results in diarrhea. When tested, women with the symptom of diarrhea during menstruation test for a higher amount of prostaglandins in their bowel.
Alternatively, women who produce fewer prostaglandins might be affected by constipation during menstruation. Diarrhea or constipation usually begins in the week before menstruation and can continue throughout the menstruation period. These symptoms are also often accompanied by nausea and indigestion. These symptoms can be easily managed with medication or adjusted eating habits and, as with all symptoms, are different for all women depending on their individual bodies and how they react to these chemical changes during the menstrual cycle.