From the point of view of medical theory, it is not advisable to have sexual intercourse during pregnancy. However, few couples can insist on not having intercourse during the whole long October pregnancy, so couples can have appropriate sex without affecting the baby. However, to avoid miscarriage, try not to have intercourse during the first and second trimesters of pregnancy. The situation of the fetus and the pregnant woman in the middle of pregnancy is relatively stable and can be decided according to the situation. In the early stage of pregnancy (1-3 months), the placenta has not yet finished developing and is in an unstable state, and the secretion of progesterone to maintain the stability of the fetus is not yet sufficient, so miscarriage is most likely to occur. In addition, the semen contains prostaglandins, which can stimulate the uterus to contract and also easily lead to miscarriage, so you should try to avoid intercourse during this period. In the middle of pregnancy (i.e. after 4 months), the development of the placenta is complete, the fetus is more stable in the uterus, the risk of miscarriage is greatly reduced, the early reaction of pregnant women disappears, the secretion of the sexual organs increases, and sex can be moderate, but should be moderate. In the later stages of pregnancy, especially the last month of pregnancy, sexual intercourse will bring bacteria into the vagina, once the delivery, bacteria in the body upstream can cause serious infection during or after delivery, and in serious cases will threaten the life of mother and child. In addition, intercourse in the second trimester is also likely to lead to premature birth, so this period should also avoid intercourse.