Are there characteristics of the false-negative cases from the first trimester combined screening programme for Down syndrome?

Abstract

Purpose of review: To review if there are any characteristics of false-negative cases from the first trimester combined screening programme for Down syndrome and by that to stimulate new approaches for improvements of the screening performance.

Recent findings: We are aware of only two studies based on screening results of false-negative cases. Screening results from false-negative cases show that maternal age is lower, nuchal translucency smaller, pregnancy-associated plasma protein-A level higher, β-human chorionic gonadotropin level lower and crown-rump length bigger than among true positive cases. Around 50% of false-negative cases had a final risk between 1 : 300 and 1 : 1000. There might also be a difference in maternal smoking status, conception method, ethnicity and weight discrepancy between false-negative and true positive cases. New biomarkers and secondary sonographic markers may also characterize false-negative cases, but investigations on these subjects have not been done so far. Finally, we think that the organization of a screening programme in all its details is a very important factor when it comes to optimizing screening performance.

Summary: Screening parameters of false-negative cases tend toward the values of unaffected pregnancies with lower maternal age, smaller nuchal translucency, higher pregnancy-associated plasma protein-A level, lower β-human chorionic gonadotropin level and bigger crown-rump length than among true positive cases.