A condition in which the placenta is situated wholly or partially in the lower and noncontractile part of the uterus. When this becomes elongated and stretched during the last few weeks of pregnancy, and the cervix becomes stretched either before or during labour, placental separation and haemorrhage will occur. The cause is not known. In the more severe degrees of placenta praevia, where the placenta is situated entirely before the presenting part of the fetus, delivery must be by Caesarean section. In lesser degrees of placenta praevia, vaginal delivery may be considered.
Subjects: Medicine and Health.