The effects of sex during pregnancy are mainly the following: 1. Due to changes in hormone levels during pregnancy, the vaginal environment of pregnant women has also changed, the vaginal mucosa is very rich in blood vessels during pregnancy, and sex during pregnancy is likely to increase the probability of vaginal inflammation. 2. Therefore, it is important to pay attention to sexual intercourse during pregnancy, as it is not allowed during the first three months of pregnancy and the second two months of pregnancy. In the 4-7 months of pregnancy, if the pregnant woman is stable, the fetus is still developing well and there are no other complications, you can have sex moderately, but you must pay attention to the frequency and intensity of sex.