5Zlatnik MG,Cheng YW,Norton M,et al.Placenta previa and the risk of preterm delivery.The Journal of Matemal-F et al.and Neo-natal Medicine,2007,20(10):719-723.
6Olive EC,Roberts CL,Algert CS,et al.Placenta praevia:mater-nal morbidity and place of birth.Australian and New Zealand Jour-nal of Obstetrics and Gynaecology,2005,45:499-504.
7Gottesfeld KR,Thompson HE,Holmes JH,et al.Ultrasonic pla-centography; a new method for placental localisation.American Journal of Obstetrics and Gynecology,1966,96:538-547.
8Edelstone DI.Placental localization by ultrasound.Clinical Obstet-rics and Gynecology,1977,20:285-296.
9Sunna E,Ziadeh S.Transvaginal and transabdominal ultrasound for the diagnosis of placenta praevia.Journal of Obstetrics and Gynae-cology,1999,19(2):152-154.
10Hertzberg BS, Livingston E, Delong DM, et al. Ultrasonographic evaluation of the cervix: transperineal versus endovaginal imaging [ J ]. J Ultrasound Med,2001,20(10) : 1071 - 1078.
1Rac M W,Wells C E,Twickler D M,et al.Placenta accreta and vaginal bleeding according to gestational age at delivery[J].Obstet Gynecol,2015,125(4):808-813.
2Cho H Y,Hwang H S,Jung I,et al.Diagnosis of placenta accreta by uterine artery doppler velocimetry in patients with placenta previa[J].J Ultrasound Med,2015,34(9):1571-1575.
3Nohuz E,Boulay E,Albaut M,et al.How I do the antenatal diagnosis of a vasa previa with ultrasound[J].Gynecol Obstet Fertil,2015,43(9):619-622.
4Rombauts L,Motteram C,Berkowitz E,et al.Risk of placenta praevia is linked to endometrial thickness in a retrospective cohort study of 4537 singleton assisted reproduction technology birth[J].Hum Reprod,2014,29(12):2787-2793.