Hook E B, Cross P K
J Med Genet. 1981 Feb;18(1):29-30. doi: 10.1136/jmg.18.1.29.
In New York State exclusive of New York City the standardised rate of Down syndrome in livebirths to women 35 and over reported on birth certificates increased 30% in 1970 and later years, compared to the rate in 1965 and 1969. In contrast, there was no change in those under 35. A separate investigation revealed that selective temporal differences in reporting of cases born to older mother did not account for the change. A similar increase in rates of cases born to older but not younger mothers in 1970 and later years has also been reported from Manitoba. These observations may be pertinent to apparent discrepancies between livebirth rates of Down syndrome and those reported at amniocentesis.
在纽约州（不包括纽约市），出生证明上报告的35岁及以上女性活产儿中唐氏综合征的标准化发病率在1970年及以后几年比1965年至1969年期间增长了30%。相比之下，35岁以下女性的发病率没有变化。另一项调查显示，老年母亲所生孩子病例报告中的选择性时间差异并不能解释这一变化。马尼托巴省也报告了1970年及以后几年老年母亲而非年轻母亲所生孩子病例发病率的类似增长。这些观察结果可能与唐氏综合征活产率和羊膜穿刺术报告率之间明显的差异有关。
