Sex during pregnancy is related to miscarriage and premature birth, but it is not a direct cause of miscarriage and premature birth, but only a precipitating factor. If the pregnant woman and the fetus are not abnormal, moderate sex life caused by miscarriage chances are very small, on the contrary, choose the right position, pay attention to matters related to also help pregnant women to maintain a relaxed state of mind, reduce pregnancy discomfort, enhance the relationship between husband and wife. However, the following aspects need to be noted: the number of intercourse should be controlled in early pregnancy, each intercourse should be short, shallow penetration, light movements, the specific degree of control to which there is no definite, subject to the comfort of pregnant women; secondly, special attention should be paid to hygiene before and after intercourse, both sides wash their hands and external genitalia to reduce the risk of infection; in addition, special attention should be paid to avoid blowing during oral sex, because the air entering the In addition, special attention should be paid to avoid blowing air during oral sex, because the air entering the vagina may cause air embolism if it accidentally enters the blood vessels, and in serious cases, pulmonary embolism in pregnant women, which is very dangerous. Of course, it is recommended to strictly avoid sexual intercourse if the following conditions exist: unexplained vaginal bleeding, previous history of miscarriage or preterm delivery, current risk of miscarriage or preterm delivery, low placenta or placenta praevia, cervical insufficiency, hypertension during pregnancy, twin or multiple pregnancies, history of cesarean section or myomectomy, inflammation of the reproductive tract in both partners, etc. In conclusion, if the indicators of pregnant women and fetus are normal in early pregnancy, you can have sex moderately, but you should try to avoid orgasm, while choosing to ejaculate outside the body, especially in early and late pregnancy, because nipple stimulation, orgasm and prostaglandins in semen can cause uterine contractions, which are generally mild and may induce miscarriage or preterm delivery in severe cases.