The reason is that there is no follicle discharge during the menstrual period, but intercourse when the period is not completely clean can easily cause inflammation and infection, which can cause endometritis and pelvic inflammatory disease in women and can cause abdominal pain. In addition, when the menstruation is not completely clean, intercourse is also likely to cause endometriosis, which can cause adenomyosis and cause menstrual pain in the future. During the menstrual period, women are prone to gynecological diseases because of their low body resistance and open uterus, so women should not have sex or take a bath during the menstrual period. During the menstrual period, you should also pay attention to keep your vulva clean and hygienic, change your sanitary pads regularly, and abstain from eating cold, spicy and stimulating foods during the menstrual period.