The chance of the placenta praevia growing up is about 80%-90%, and whether the placenta praevia can grow up depends mainly on the stage of pregnancy. If the placenta praevia is found during an ultrasound in the middle of pregnancy, there is no need to worry too much. As the gestation period increases and the pregnancy progresses, the lower part of the female uterus will gradually form, thus there is a certain possibility that the female placenta will move away from the cervical position. There is a 90% chance that the placenta is not placenta praevia at the time of delivery. When placenta praevia is found during ultrasound examination in late pregnancy, it is less likely to return to normal state and needs to be treated as placenta praevia. It is recommended that women should have the appropriate checkups during pregnancy and also closely observe the placenta changes, because placenta praevia can easily lead to irregular vaginal bleeding and even hemorrhage during delivery.