The birth prevalence rate of each common autosomal trisomy generally increases with advancing maternal age and there is a substantial fetal loss rate between late first trimester and term. The literature is reviewed in order to provide the best estimates of these rates, taking account where possible of biases due to prenatal diagnosis and selective termination of pregnancy. There is an almost exponential increase in Down syndrome birth prevalence between ages 15 and 45 but at older ages the curve flattens. There is no evidence of the claimed relatively high birth prevalence at extremely low ages. Gestation‐specific intra‐uterine fetal loss rates are estimated by follow‐up of women declining termination of pregnancy after prenatal diagnosis, comparison of observed rates with those expected from birth prevalence and comparison of age‐specific curves developed for prenatal diagnosis and birth. Down syndrome fetal loss rates reduce with gestation and increase with maternal age. Edwards and Patau syndrome birth prevalence is approximately 1/8 and 1/13 that of Down syndrome overall, although the ratio differs according to maternal age, particularly for Patau syndrome where it reduces steadily from 1/9 to 1/19. Fetal loss rates are higher for Edwards and Patau syndromes than for Down syndrome.

中文翻译：

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常见常染色体三体性流行病学中的孕产妇年龄

每个常见的常染色体三体性的出生率通常随着母亲年龄的增长而增加，并且在早孕晚期和足月之间存在大量的胎儿丢失率。审查文献以提供这些比率的最佳估计，并在可能的情况下考虑由于产前诊断和选择性终止妊娠而产生的偏差。唐氏综合症出生率在 15 至 45 岁之间几乎呈指数增长，但在年龄较大时，曲线趋于平缓。没有证据表明在极低年龄阶段的出生率相对较高。通过对产前诊断后拒绝终止妊娠的妇女进行随访，估计特定妊​​娠的宫内胎儿丢失率，将观察到的比率与出生流行率预期的比率进行比较，并比较为产前诊断和出生制定的特定年龄曲线。唐氏综合症胎儿丢失率随着妊娠而降低，随着母亲年龄的增加而增加。Edwards 和 Patau 综合征的出生患病率大约是唐氏综合征的 1/8 和 1/13，尽管这一比例因母亲年龄而异，尤其是 Patau 综合征，它从 1/9 稳步下降到 1/19。Edwards 和 Patau 综合征的胎儿丢失率高于唐氏综合征。特别是对于 Patau 综合征，它从 1/9 稳步下降到 1/19。Edwards 和 Patau 综合征的胎儿丢失率高于唐氏综合征。特别是对于 Patau 综合征，它从 1/9 稳步下降到 1/19。Edwards 和 Patau 综合征的胎儿丢失率高于唐氏综合征。