虽35岁以上的孕妇分娩 Down 氏综合征婴儿的危险性增加,但在此年龄组的病儿仅占全部病儿的20%。如对15～34岁年龄组孕妇用羊膜穿刺、细胞培养、胎儿核型分析等现代检查方法虽可查出更多的本症患者,但实际上是不经济的。因此,要减少Down 氏综合征的患儿,就需要一种安全可靠经济的方法来确定哪个年龄组孕妇可能分娩患儿。早已 Although pregnant women over the age of 35 have Down’s syndrome increased risk of childbirth, but in this age group of sick children accounted for only 20% of all sick children. If the pregnant women in the 15 to 34 age group with amniocentesis, cell culture, fetal karyotype analysis and other modern inspection methods can detect more of the patients, but in fact it is not economical. Therefore, to reduce children with Down’s syndrome, a safe and reliable method is needed to determine which age group of pregnant women may give birth to children. Already