The first thing you need to do is to look at the situation after 15 weeks of pregnancy and observe that there is no abnormality. If there is any abnormality, you should consult a doctor in time, and according to the development of the fetus, you should consider the treatment of birth control or termination of pregnancy. The development of the fetus in the uterus at 15 weeks of pregnancy is relatively stable, and it will not necessarily have an impact on the coitus, and there is no abnormal vaginal bleeding, abdominal pain and other symptoms observed after coitus, indicating that there is not much impact on the fetus, and it can be temporarily observed first. If there is abnormal vaginal bleeding, abdominal pain and other symptoms after intercourse in the 15th week of pregnancy, we need to be vigilant that the uterine contraction is stimulated after intercourse, resulting in fetal abortion, at this time, we should go to the hospital to check the development of the fetus in the womb, if necessary, can be carried out on birth control treatment. If there is a large amount of vaginal bleeding, abdominal pain and other symptoms, through the examination can not be treated by abortion, the need for timely induced termination of pregnancy. Therefore, it is recommended that mid-pregnancy coitus should not be too strenuous, the number of coitus should not be too frequent, and the abnormalities after coitus should be promptly consulted.