Anterior placenta is most dangerous in late pregnancy, between the seventh month of pregnancy and the time of delivery. Placenta praevia is a serious complication of pregnancy and can endanger the life of the mother and fetus at any time if not treated properly. Because placenta praevia occurs mainly after late pregnancy, the amount of bleeding can be high or low, the time of bleeding can be early or late, and the number of bleeding can be multiple, mainly related to the type of placenta praevia. The amount of bleeding and the degree of risk vary between different types of placenta praevia, which are mainly classified as complete placenta praevia, partial placenta praevia and borderline placenta praevia according to the placenta and the endocervix. Among them, the first bleeding of complete placenta praevia is earlier, mostly at the end of the mid-term period of pregnancy, with more repeated bleeding and more bleeding. Therefore, before 28 weeks of pregnancy, the placenta is low lying state, and after 28 weeks placenta praevia should be checked regularly before delivery regardless of the bleeding symptoms, and once the painless bleeding occurs, you should seek medical attention immediately to avoid delaying the condition.