Townsend R R, Filly R A
Department of Radiology, University of California, San Francisco.
J Ultrasound Med. 1988 Dec;7(12):665-70. doi: 10.7863/jum.1988.7.12.665.
Five nonconjoined monoamniotic twin pregnancies were identified prenatally by sonography. In all cases the diagnosis was made when umbilical cords of the two fetuses were seen to be entangled. One monoamniotic twin pregnancy was not recognized prenatally because the cords were not seen to be entangled. Although monoamniotic twins frequently die related to cord knotting, sonographic visualization of cord entanglement does not imply impending demise. Visualization of cord entanglement appears to be specific for the diagnosis of monoamnionicity, but the sensitivity is not known. Prenatal diagnosis allows informed planning of obstetrical monitoring and mode of delivery.
通过超声检查在产前识别出5例非联体单绒毛膜双胎妊娠。所有病例均在看到两个胎儿的脐带相互缠绕时做出诊断。有1例单绒毛膜双胎妊娠在产前未被识别，因为未发现脐带相互缠绕。虽然单绒毛膜双胎常因脐带打结而死亡，但超声显示脐带缠绕并不意味着即将死亡。脐带缠绕的显示似乎是诊断单绒毛膜双胎的特异性表现，但敏感性尚不清楚。产前诊断有助于对产科监测和分娩方式进行明智的规划。
