Women should not have sex in the first and second trimesters of pregnancy, mainly because the embryo is still unstable in the first trimester, and sex may cause contraction of the uterine smooth muscle and lead to peeling of the gestational sac from the uterine wall, which may lead to vaginal bleeding, miscarriage, lower abdominal pain and other corresponding symptoms. If you have sex in the second three months of pregnancy may cause premature labor, intrauterine infection or the possibility of premature rupture of membranes, so it is recommended that you do not have sex in the first three months and the second three months of pregnancy, and if you have sex in other time periods, you must pay attention to: 1, the frequency of sex should not be too frequent; 2, pay attention to the hygiene of sexual intercourse; 3, sexual intercourse during the process of movement must be gentle.