Search

Objective To evaluate the efficacy of first trimester combined screening for Down's syndrome in Northern Finland during the first 10 years of practice. Methods During 1 January 2002 to 31 December 2011, 47,896 women participated voluntarily in combined screening during first trimester. The risk cutoff was 1:250. The study period was divided into two time periods; 2002-2006 and 2007-2011. Results During the first half of the study period, the detection rate (DR) was 77.3% with a 4.9% false-positive rate (FPR). During the latter half, the DR was 77.1% with a 2.8% FPR. Conclusions An important issue is the number of invasive procedures needed to detect one case of Down's syndrome. The screening performance improved markedly in the latter five years period since the FPR lowered from 4.9% to 2.8% and the number of invasive procedures needed to detect one case of Down's syndrome lowered from 15 to 11.

Background: The performance of first trimester biochemical screening was compared at different pregnancy weeks and maternal ages during 2002-2008 in a screened population of 76,949 women., Methods: The detection rates, as well as the median multiples of a median (MOMs) of free β-human chorionic gonadotropin (free β-hCG) and pregnancy-associated plasma protein-A (PAPP-A), were compared between completed gestational weeks 8-13 and between different maternal ages separated into 5-year groupings., Results: The number of singleton Down syndrome pregnancies was 221. The median age of the screened women was 30 years and the proportion of women aged ≥ 35 years 16.9%. The median age of the women with a Down syndrome pregnancy was 37 years. In women aged <35 years, the biochemical markers provided a detection rate of only 38.6%, whereas in women aged ≥ 35 years, the biochemical markers detected 82.7% of cases (p<0.01)., Conclusions: Biochemical screening works best amongst women aged ≥ 35 years. For younger mothers aged <35 years, combined screening should be the method of choice.