Why central placenta previa?

Central placenta previa refers to the placenta completely covered in the cervical orifice after 28 weeks of pregnancy, resulting in persistent painless bleeding. It is mainly caused by the intense implantation position of the fertilized egg too close to the cervical orifice. If the pregnancy time is less than 34 weeks, magnesium sulfate can be used to protect the fetus, but if the pregnancy time is greater than 34 weeks, dexamethasone can promote embryo maturity, early termination of pregnancy.