Having an orgasm while pregnant can cause the uterus to contract, as the uterus is relatively sensitive to the effects of estrogen and will contract when stimulated by external forces. The consequences of uterine contractions may often lead to the peeling off of the pregnancy sac from the uterine wall and vaginal bleeding. Therefore, it is recommended not to have sex during the first trimester of pregnancy to avoid miscarriage due to sex. In addition, in the middle of pregnancy, you can have sex, but you have to give appropriate moderation. If you have sex too often, it may lead to frequent contractions of the uterus, which may cause the fetus to suffer from lack of oxygen in the uterus. Therefore, it is recommended to have sex in mid-pregnancy with gentle movements and at longer intervals to avoid uterine contractions caused by too frequent intercourse.