Lowry R B, Jones D C, Renwick D H, Trimble B K
Teratology. 1976 Aug;14(1):29-34. doi: 10.1002/tera.1420140105.
Records of children with Down syndrome (DS) at the BC Health Surveillance Registry were linked to their Birth Registrations to derive maternal ages. Incidence and maternal-age specific rates were calculated for 1952-73. Mean maternal age has declined both for normal and DS children, the latter to a marked degree, so that in 1972-73 80% were born to women under 35 years. Using maternal age of 40 and over as an indication for amniocentesis would only detect 10% of DS children. The crude incidence rate (mean 1.28/1000 livebirths) has not changed appreciably over the study period except for 1969 in which a statistically significant peak occurred. The standarized rate showed an increasing trend but it is not clear whether this was a true biological increase or resulted from better ascertainment.
卑诗省健康监测登记处中唐氏综合征（DS）患儿的记录与其出生登记信息相关联，以得出母亲年龄。计算了1952年至1973年的发病率和按母亲年龄划分的特定发病率。正常儿童和DS患儿的母亲平均年龄均有所下降，后者下降幅度明显，因此在1972年至1973年，80%的患儿母亲年龄在35岁以下。以40岁及以上的母亲年龄作为羊膜穿刺术的指征，只能检测出10%的DS患儿。除1969年出现统计学上显著的峰值外，在研究期间粗发病率（平均1.28/1000活产）没有明显变化。标准化率呈上升趋势，但尚不清楚这是真正的生物学增加还是由于更好的确诊所致。
