It is not recommended to have intercourse during the first and second trimesters of pregnancy, but in the middle of pregnancy you can have intercourse in moderation, but you need to pay attention to the intensity and frequency of intercourse, not too frequent and not too strong. If you have intercourse in the early stages of pregnancy and do not pay attention to control, it will easily cause miscarriage. If in late pregnancy, the fetus grows and the uterus increases more significantly, then if you have intercourse, it will easily lead to an increase in the chances of preterm delivery. The reason is that after the fetus is in the pelvis in late pregnancy, the cervical canal becomes shorter and the cervical opening is in a slightly dilated state. If too much force is exerted at this time, it may cause the amniotic sac to rupture and the amniotic fluid to flow out, or it may lead to premature placental contraction, causing the uterus to contract violently, which may cause the possibility of bleeding.