孕母血清唐氏综合征筛查中针对孕周进行的风险评估调整。

Risk assessment adjusted for gestational age in maternal serum screening for Down's syndrome.

作者信息

Gardosi J, Mongelli M

机构信息

Department of Obstetrics and Gynaecology, Queen's Medical Centre, Nottingham.

出版信息

BMJ. 1993 Jun 5;306(6891):1509-11. doi: 10.1136/bmj.306.6891.1509.

DOI:10.1136/bmj.306.6891.1509

PMID:8518678

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1677930/

Abstract

OBJECTIVE

To investigate the relation between errors in calculation of gestational age and assessment of risk of Down's syndrome and to analyse the implications for screening programmes.

DESIGN

Retrospective analysis of dating of gestational age by menstrual history v ultrasound scan. Computer program with maternal age and concentrations of alpha fetoprotein and free beta human chorionic gonadotrophin to calculate risk for a range of expected dates of delivery. Computer simulated prospective application of new screening programme.

SETTING

Teaching hospitals in Nottingham.

SUBJECTS

31,561 women with singleton pregnancies with gestational age based on routine ultrasound scan. Computer simulation of 20,000 women in three age ranges (up to 37; up to 40; all).

MAIN OUTCOME MEASURES

Distribution of error between gestational age based on ultrasound scan v menstrual history. Proportion of women in the population who require precise dating of pregnancy; proportion of women who require amniocentesis.

RESULTS

With gestational age derived from ultrasound scan as reference the 95% confidence interval for gestational age by menstrual history was -27 to +9 days. A screening programme for Down's syndrome for women up to age 40 would yield a low risk (< 1:250) for this range of days in 86.0% of cases. The 14.0% of women remaining would have one or more high risk values in their report and would thus require an ultrasound scan for precise dating of the pregnancy; 30% of these--that is, 3.7% of the screened population--would be identified as high risk and require consideration for amniocentesis.

CONCLUSIONS

Screening programmes for Down's syndrome require the facility for precise dating of pregnancy to improve the accuracy of risk assessment. This can be achieved without introducing additional scans for early dating in the whole population but by selecting only those cases (about 14%) when an error in dates is likely to affect the risk of Down's syndrome.

摘要

目的

研究孕周计算误差与唐氏综合征风险评估之间的关系，并分析其对筛查项目的影响。

设计

通过月经史与超声扫描对孕周进行回顾性分析。利用计算机程序结合孕妇年龄、甲胎蛋白和游离β-人绒毛膜促性腺激素浓度，计算一系列预期分娩日期的风险。对新筛查项目进行计算机模拟前瞻性应用。

地点

诺丁汉的教学医院。

研究对象

31561名单胎妊娠妇女，其孕周基于常规超声扫描确定。对三个年龄范围（37岁及以下；40岁及以下；所有年龄）的20000名妇女进行计算机模拟。

主要观察指标

基于超声扫描的孕周与月经史孕周之间的误差分布。人群中需要精确确定孕周的妇女比例；需要进行羊膜穿刺术的妇女比例。

结果

以超声扫描得出的孕周为参考，月经史孕周的95%置信区间为-27至+9天。针对40岁及以下妇女的唐氏综合征筛查项目，在该孕周范围内，86.0%的病例风险较低（<1:250）。其余14.0%的妇女报告中会有一个或多个高风险值，因此需要进行超声扫描以精确确定孕周；其中30%（即筛查人群的3.7%）会被确定为高风险，需要考虑进行羊膜穿刺术。