It is not allowed to have intercourse during menstruation. During menstruation, the body’s resistance decreases, so if you have intercourse during menstruation, it can cause gynecological infections, resulting in vaginitis, cervicitis, pelvic inflammatory disease, etc. During menstruation, the endometrium sheds, causing the cervical opening to open, and menstrual blood remains in the vagina. Having intercourse during menstruation can cause menstrual blood to flow backwards, which can easily cause endometriosis, aggravate menstrual pain, and cause increased menstrual flow and prolonged periods. If you have intercourse during menstruation, you need to have regular checkups, and if you have gynecological infections, you need to go to the hospital gynecology department in time for examination and active symptomatic treatment to avoid delay and aggravation of the condition.