It is safe to have intercourse after three days of menstruation, when the residual endometrial tissue and accumulated blood in the uterine cavity and vagina have been completely discharged, and the cervix is closed, so it is possible to have intercourse. During menstruation and one or two days after menstruation, due to the cervical opening, pathogens can enter the uterine cavity through the cervical opening during coitus, leading to vaginitis, endometritis, adnexitis, endometrium can be planted outside the uterus or uterine cavity during coitus, resulting in adenomyosis, endometriosis, which can cause infertility in severe cases, and coitus during menstruation can easily lead to anti-sperm antibodies. Positive, immune infertility, so during menstruation can not be coitus, and coitus after three days of menstruation is safer. During menstruation, women should keep the vulva clean and dry, change sanitary napkins regularly, pay attention to keep warm, avoid getting cold, pay attention to rest, avoid exertion, and pay attention to ensure that the intake of nutritious food in order to improve the body’s immunity.