In general, it is forbidden to have intercourse until the period is completely cleared. If you have intercourse at this time, the following potential risks may occur: First, it may lead to an increase in menstrual flow. Second, it may lead to the prolongation of the menstrual period, the period usually lasts between 2-8 days, at this time coitus may be manifested in the prolongation of the menstrual period, the menstrual dribbling. Third, may be in the process of coitus with bacteria or viruses, causing pelvic infection, may be manifested as vaginal infection, may also be manifested as pelvic inflammatory disease, endometritis and so on. If there are no symptoms of infection, it is generally not recommended to use medication in advance, you can consider oral proprietary medicines, such as Kangwuyan capsule to prevent infection, but at this time it is generally not recommended to blindly use antibiotics to prevent infection. The same period of intercourse may also cause pregnancy without contraception, but the chances are still relatively small, because the endometrium is in the process of shedding during menstruation, the risk of pregnancy is not great, but can not be completely avoided, must pay attention to.