Hi, ano po ibig sabihin ng Anterior totally covering the OS

As of my research, Placenta previa occurs when a baby's placenta partially or totally covers the mother's cervix — the outlet for the uterus. Placenta previa can cause severe bleeding during pregnancy and delivery. If you have placenta previa, you might bleed throughout your pregnancy and during your delivery. Your health care provider will recommend avoiding activities that might cause contractions, including having sex, douching, using tampons, or engaging in activities that can increase your risk of bleeding, such as running, squatting, and jumping. You'll need a C-section to deliver your baby if the placenta previa doesn't resolve.