It is not recommended to have intercourse on the first day of menstruation. The first day of menstruation, the cervix is not completely closed, it is easy to cause female reproductive tract infection, such as vaginitis, cervicitis, endometritis and so on. If you have intercourse on the first day of menstruation, it will lead to pelvic congestion, which will make the newly repaired uterine lining shed again and cause a small amount of vaginal bleeding, and some of them will last for several days, so it is best not to have intercourse on the first day of menstruation. Usually three days after the menstrual period can resume sexual intercourse, pay attention to hygiene, wash the perineum with warm boiled water, good personal care, to prevent infection. If you have abdominal pain and other discomfort during sex, stop in time and go to a regular hospital to avoid adverse consequences.