The impact of coitus on the fetus during pregnancy needs to be assessed according to the pregnant woman’s pregnancy cycle, fetal development, and the pregnant woman’s own situation. Generally speaking, mid-pregnancy can be appropriate cohabitation, early and late pregnancy is not recommended cohabitation. 1, early pregnancy: refers to the pregnancy before 12 weeks, is the fertilized egg implantation, embryonic development of the critical period, in this time the fetus will be basically developed, the state is not stable, if cohabitation is prone to cause miscarriage. And most pregnant women nausea, vomiting and other early pregnancy reaction is obvious, low libido, sexual response is weakened, no matter from which side of the consideration is not suitable for coitus; 2, mid-pregnancy: refers to the 13-28 weeks of pregnancy, the fetus development is basically shaped, in the uterine cavity is more stable, the pregnant woman’s early pregnancy reaction is weakened or disappeared, the body’s sex hormone level increases, sexual response is sensitive. If the pregnant woman does not have abdominal pain, flow of brown secretions and other uncomfortable conditions, pay attention to the position, frequency and strength of the coitus, it is possible to coitus, generally will not have an impact on the fetus. However, if the action is too aggressive, stimulate uterine contraction, there will also be preeclampsia, premature rupture of membranes and other risks; 3, late pregnancy: refers to the 28 weeks of pregnancy to the delivery, because of the development of the fetal volume in the uterine cavity increases, pregnant women abdominal bulge is larger, the fetal movement is obvious, the body is gradually bulky and heavy, the waist weight is also increasing, and is not suitable for coitus. This time period is more likely to cause contractions, which may cause premature rupture of membranes and premature delivery of the fetus.