Classification Total placenta previa The internal cervical os is covered completely by pl Macenta Partial placenta previa The internal os is partially covered by placenta Marginal placenta previa The edge of the placenta is at the margin of the intenal osClassification • Total placenta previa The internal cervical os is covered completely by placenta • Partial placenta previa The internal os is partially covered by placenta • Marginal placenta previa The edge of the placenta is at the margin of the intenal os