The third and a half months of pregnancy is the middle of pregnancy, the fetus is basically developed, in general, can be appropriate intercourse. But the number of intercourse needs to pay attention to moderation, not too frequent, and moderate strength, be careful not to press the pregnant woman’s abdomen, so as not to produce huge pressure on the uterus, leading to increased chances of miscarriage. In addition, men and women should wash their vulva before intercourse, and women should urinate in time after intercourse, and wash their vulva to prevent infection, and the woman should not be too excited, and the time should not be too long, otherwise it is easy to induce uterine contractions. It should be noted that the first and last trimesters of pregnancy should be prohibited from having intercourse because the fetus is still unstable in the first trimester and the progesterone secretion is insufficient, so intercourse at this time may lead to the risk of miscarriage, and the pregnant woman is usually emotionally disturbed by early pregnancy at this time, which is not suitable for intercourse. In the second trimester, the placenta begins to descend, the pregnant woman’s hands and feet will be more edematous, and may have difficulty moving, so intercourse at this time is also likely to cause contractions, leading to premature delivery. In addition, during pregnancy, it is important to observe whether there is vaginal bleeding and stomach pain, if this occurs, even in the middle of pregnancy, sexual intercourse should be prohibited, and need to pay attention to timely re-examination.