4Chaurasia SD.Single umbilical with caudal defects in human fetuses[J].Teratology,1974,9 (3):287-297.
5Jeanty P. Persistent right umbilical vein: an ominous prenatal finding? Radiology, 1990,177 : 735-738.
6De Carte L, Osmanagaoglu K, De Schriiver I. Persistent right umbilical vein in trisomy 18: sonographic observation. J Ultrasound Med, 1998,17:775-779.
7Sherer DM,Anyaegbunam A.Prenatal ultrasonographic more pathologic assessment of the umbilical cord:a review[J].Obstet Gynecol Surv,1997,52(8):506.
8Persutte WH,Hobbins J.Single umbilical artery:a clinical e-nigma in modern prenatal diagnosis[J].Ultrasound Obstet Gynecol,1995,6(3):216.
9Rembouskos G,Cicero S,Longo D et al.Single umbilical ar-tery at 11-14 weeks'gestation:relation to chromosomal defects[J].Ultrasound Obstet Gynecol,2003,22(6):567.
10Martinez-Frias ML,Bermejo E,Rodriguez-Pinilla E et al.Does single umbilical artery(SUA)predict any type of congenital defect?Clinical epidemiological analysis of a large consecutive series of malformates infants[J].Am J Med Genet A,2008,146(1):15.
