The 5th day of menstruation time to have sex, when the menstruation is not completely clean, the mouth of the uterus is in an open state. After intercourse may make the amount of menstruation abnormal, and also increase the chance of infection in the uterine cavity. If you have already had intercourse during menstruation, pay attention to the cleanliness and care of the perineum, and wash the perineum. At the same time, observe whether you will have increased vaginal bleeding, abdominal pain, abnormal color and character of leukorrhea, may be vaginitis or cervical inflammation, it is recommended to go to the hospital to do the relevant examination, diagnose the cause of the disease, and then symptomatic medication. It is recommended to have intercourse about 2-3 days after the menstruation is completely clean, which will be better for women.