If you have intercourse when you have your period: 1. If you have stomach pain immediately after intercourse, it is likely that the stimulation of intercourse has caused uncoordinated contractions of the uterus. The actual fact is that you can have a bowl of hot brown sugar and ginger water to warm up the uterus and make the menstrual blood flow more smoothly, slowing down the symptoms of stomach pain. 2. If you have stomach pain a few days after having intercourse, it is likely that the infection has caused pelvic inflammatory disease causing pain. The actual fact is that you can find a lot of people who are not able to get a good deal on a lot of things. Intercourse during menstruation may lead to infection and may also lead to endometriosis, so do not have intercourse during menstruation.