Aymé S, Julian C
INSERM U242, Hôpital d'enfants de la Timone, Marseille.
Rev Epidemiol Sante Publique. 1991;39 Suppl 1:S65-73.
Two procedures of prenatal diagnosis were the subject of epidemiological evaluations. The first one is the screening of Down syndrome among pregnant women 38 years of age and over. The other is the antenatal screening of major malformations by ultrasound. An analysis of the different studies published is presented. The interventions are defined and the frequencies of pathologies involved are given. A review of risks, efficacy and effectiveness of each intervention was then carried out. For Down syndrome screening, the criterion for efficacy and effectiveness is the case prevented. Maximum expected efficacy if the attendance of pregnant women 38 years and over to amniocentesis was 100% is 21%. In practice, the effectiveness (24%) is higher than the efficacy (21%) for the Bouches du Rhône district because health care channels to amniocentesis are not based only on the indication of maternal age. During these last three years in the Bouches du Rhône area, 25% of the trisomies 21 detected were so because amniocentesis was carried out after an abnormal sonographic sign had been detected, and 75% because of maternal age. The limitations of the effectiveness are detailed. For the ultrasound screening of major malformations, the efficacy and the effectiveness are assessed through the intermediate criterion of "number of antenatal diagnoses performed". The overall sensitivity of screening in the general population varied between 55% and 75% according to the studies but it was only between 28% and 39% at the 24th week of gestation. The most often screened anomalies were of the central nervous system and the least often screened were congenital cardiopathies. The two interventions were then compared for their objectives and limitations.
两项产前诊断程序成为了流行病学评估的对象。第一项是对38岁及以上孕妇进行唐氏综合征筛查。另一项是通过超声进行主要畸形的产前筛查。本文对已发表的不同研究进行了分析。明确了干预措施并给出了所涉及病症的发生率。随后对每项干预措施的风险、疗效和效果进行了综述。对于唐氏综合征筛查，疗效和效果的标准是预防的病例数。如果38岁及以上孕妇进行羊膜穿刺术的参与率为100%，最大预期疗效为21%。在实践中，罗讷河口省的效果（24%）高于疗效（21%），因为通往羊膜穿刺术的医疗保健渠道并非仅基于母亲年龄这一指标。在罗讷河口地区的过去三年里，所检测出的21三体病例中有25%是因为在检测到超声异常征象后进行了羊膜穿刺术，75%是因为母亲年龄。详细阐述了效果的局限性。对于主要畸形的超声筛查，疗效和效果是通过“进行的产前诊断数量”这一中间标准来评估的。根据研究，普通人群筛查的总体敏感性在55%至75%之间，但在妊娠第24周时仅在28%至39%之间。筛查最频繁的异常是中枢神经系统方面的异常，筛查最少的是先天性心脏病。然后对这两项干预措施的目标和局限性进行了比较。
