Placental abnormalities such as placenta previa, in which the placenta attaches low in the uterus and covers the cervix; placenta accreta, in which the entire placenta or parts of the organ penetrate too deeply into the uterine wall and cannot detach after birth; and preeclampsia, in which the organ’s blood vessels do not form properly, leading to high blood pressure and dangerous conditions late in pregnancy, can cause difficult and frightening births, even maternal death.
