用绒毛作直接染色体分析正在成为一种早孕产前诊断的常规方法,仅需数小时就可以从自然分裂的细胞滋养层获得结果。现已假定,用直接法所得出的中期分裂相来自胎儿。作者报导,从绒毛和蜕膜相混的标本中,用直接法发现有母体的中期分裂相。作者对一位已经生育一个21三体孩子的25岁患者进行绒毛活检。用常规胰酶消化直接法得到绒毛细胞。在同一活检标本中,一份是经过仔细挑选的绒毛标本,一份是有母体蜕膜污染的绒毛标本。在约 Chorionic villus analysis is becoming a routine method of prenatal diagnosis of early pregnancy, and results can be obtained from naturally dividing cytotrophoblasts in hours. It has been postulated that the metaphase split phase obtained by the direct method comes from the fetus. The authors report that maternally split metaphases were found by direct methods from specimens mixed with villi and decidua. The authors performed a villus biopsy of a 25-year-old patient who had given birth to a trisomy 21. Villus cells were obtained by direct digestion with conventional trypsin. In the same biopsy, one was carefully selected villus specimens, one with maternal deciduas contaminated villi specimens. At about