6Tuzovic L, Djelmis J, Ilijic M. Obstetric risk factors associated with placenta previa development: case-control study. Croat Med J, 2003, 44: 728-733.
7Johnson LG, Mueller BA, Daling JR. The relationship of placenta previa and history of induced abortion. Int J Gynaecol Obstet,2003, 81: 191-198,
8Faiz AS, Ananth CV. Etiology and risk factors for placenta previa: an overview and meta-analysis of observational studies. J Matern Fetal Neonatal Med, 2003, 13: 175-190.
9Dashe JS, McIntire DD, Ramus RM, et al. Persistence of placenta previa according to gestational age at ultrasound detection.Obstet Gynecol, 2002, 99: 692-697.
10Sherman SJ, Carlson DE, Platt LD, et al. Transvaginal ultrasound: does it help in the diagnosis of placenta previa? Ultrasound Obstet Gynecol, 1992, 2: 256-260.
1Oya A, Nakai A, Miyake H, et al. Risk factors for peripartum blood transfusion in women with placenta previa: a retrospective analysis. J Nippon Seh, 2008, 75(3): 146