Menstrual period is absolutely prohibited sex, menstrual intercourse brings harm to women’s health, mainly including: 1, the natural defense function of the female reproductive system decreases during menstruation, the ability to resist various pathogenic microbial infections decreases, and menstrual blood is a better medium for various pathogenic microorganisms, coitus during menstruation, easily lead to women suffering from endometritis, pelvic inflammatory diseases. 2, menstruation The reason for this phenomenon is that intercourse during menstruation can easily lead to gynecological infections and affect the health of the uterus, ovaries and fallopian tubes, and intercourse during menstruation can also easily lead to anti-sperm antibodies and anti-endometrial antibodies in women, causing immune infertility.