在全球范围内,见于 0.3% 至 0.5% 的妊娠。[6]Getahun D, Oyelese Y, Salihu HM, et al. Previous cesarean delivery and risks of placenta previa and placental abruption. Obstet Gynecol. 2006;107:771-778.http://www.ncbi.nlm.nih.gov/pubmed/16582111?tool=bestpractice.com[7]Loto O, Onile TG. Placenta praevia at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife. A ten year analysis. Niger J Clin Pract. 2008;11:130-133.http://www.ncbi.nlm.nih.gov/pubmed/18817052?tool=bestpractice.com[8]Yang Q, Wu Wen S, Caughey S, et al. Placenta previa: its relationship with race and the country of origin among Asian women. Acta Obstet Gynecol Scand. 2008;87:612-616.http://www.ncbi.nlm.nih.gov/pubmed/18568460?tool=bestpractice.com 发生频率部分取决于该人群的潜在危险因素。本病在第一次妊娠中不常见。在美国,由于剖宫产增加,前置胎盘的发生率在不断提高。一次剖宫产可使下次妊娠的(前置胎盘)发生率增加约 0.6%。与一次剖宫产相比,后续的剖宫产只会使风险轻微增高。预计在剖宫产比例不断增加的其他国家/地区,也会反映出(前置胎盘)发生率的增高。[6]Getahun D, Oyelese Y, Salihu HM, et al. Previous cesarean delivery and risks of placenta previa and placental abruption. Obstet Gynecol. 2006;107:771-778.http://www.ncbi.nlm.nih.gov/pubmed/16582111?tool=bestpractice.com[9]Odibo AO, Cahill AG, Stamilio DM, et al. Predicting placental abruption and previa in women with a previous cesarean delivery. Am J Perinatol. 2007;24:299-306.http://www.ncbi.nlm.nih.gov/pubmed/17514600?tool=bestpractice.com[10]Qublan HS, Tahat Y. Multiple cesarean section. The impact on maternal and fetal outcome. Saudi Med J. 2006;27:210-214.http://www.ncbi.nlm.nih.gov/pubmed/16501678?tool=bestpractice.com[11]Lynch CM, Kearney R, Turner MJ. Maternal morbidity after elective repeat cesarean section after two or more previous procedures. Eur J Obstet Gynecol Reprod Biol. 2003;106:10-13.http://www.ncbi.nlm.nih.gov/pubmed/12475574?tool=bestpractice.com 与产科的其他问题一样,有关这个主题的大多数流行病学研究都是在发达国家/地区开展的。这可能会对发生率和危险因素的评估造成影响。