During menstruation, many women experience what is often referred to as period diarrhea. Medical professionals explain that this is primarily due to prostaglandins, which are chemicals released during your cycle. These substances not only induce uterine contractions but also enhance bowel activity, resulting in more frequent and sometimes looser stools.source https://timesofindia.indiatimes.com/life-style/health-fitness/health-news/period-diarrhea-is-more-common-than-you-think-doctor-explains-why/articleshow/126044725.cms