If a low lying placenta is present, it has a greater impact and is more dangerous after 28 weeks of pregnancy. If the lower edge of the placenta is found to be less than 2 cm from the internal cervical os during ultrasound examination during pregnancy, it is called a low placental state. If found in early pregnancy, most of them can grow up in the middle and late pregnancy and may return to normal placenta position, so the risk is relatively low before 28 weeks of pregnancy. If placenta hypoplasia still exists after 28 weeks of pregnancy, it can be classified as placenta hypoplasia, marginal placenta praevia, partial placenta praevia and complete placenta praevia according to the severity, which may cause painless vaginal bleeding, and if the bleeding is heavy, timely obstetrics and gynecology consultation is needed, and depending on the situation, hospitalization for fetal preservation treatment or timely termination of pregnancy. Pregnant women with placenta praevia need to take rest, avoid sexual intercourse, and increase pregnancy checkups.