Faculty of Medicine, Tel Aviv University, Israel.
Population Health Research Institute, St George's Hospital, UK.
Prenat Diagn. 2021 Apr;41(5):573-583. doi: 10.1002/pd.5840. Epub 2020 Oct 19.
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.
每种常见常染色体三体的出生流行率通常随母亲年龄的增长而增加，并且在第一孕期末至足月之间存在大量胎儿丢失率。本文回顾了文献，以便在考虑到产前诊断和选择性终止妊娠引起的偏倚的情况下，提供这些比率的最佳估计。唐氏综合征的出生流行率在 15 岁至 45 岁之间呈几乎指数增长，但在年龄较大时曲线趋于平坦。没有证据表明在极低年龄时存在所谓的相对较高的出生流行率。通过对接受产前诊断后拒绝终止妊娠的妇女进行随访，观察率与从出生流行率中预期的比率进行比较，以及对产前诊断和出生时开发的年龄特异性曲线进行比较，来估计特定妊娠的宫内胎儿丢失率。唐氏综合征的胎儿丢失率随妊娠而降低，随母亲年龄而增加。爱德华兹和帕陶综合征的总体发病率约为唐氏综合征的 1/8 和 1/13，但与母体年龄有关，特别是帕陶综合征，其比例从 1/9 逐渐降至 1/19。爱德华兹和帕陶综合征的胎儿丢失率高于唐氏综合征。
