What does the lower margin of the placenta mean next to the internal opening of the cervix?

When the placenta is close to the internal os of the cervix

, the lower uterine contractility is strong, especially in the process of delivery, and the placenta is not easy to separate. It is easy to cause bleeding to varying degrees. In severe cases, it may cause massive bleeding, which threatens the life safety of pregnant women and fetuses. At the same time, this condition may affect the blood supply of the placenta, thus not providing sufficient nutrition and oxygen for the fetus, thus affecting the normal growth and development of the fetus, increasing the incidence of adverse pregnancy outcomes such as fetal growth restriction and premature delivery

.