Sexual intercourse after the fertilized egg has been laid may cause contractions of the uterus, which may result in miscarriage. Especially in the first trimester, when the embryo is very unstable, intercourse is very likely to cause the pregnancy sac to fall off. In the first trimester, you should try to avoid lifting heavy objects, pay attention to rest and not to have intercourse, and go to the hospital as soon as you feel unwell. It is possible to have intercourse in the middle of pregnancy, but you should pay attention to gentle movements and make sure not to compress the pregnant woman’s abdomen. It is also absolutely forbidden to have intercourse during the late pregnancy, when it is close to the date of delivery, intercourse is very likely to lead to premature birth. In addition, you need to pay attention to the entire pregnancy can not take any drugs without permission, so as not to cause fetal abnormalities.