: AFS can markedly reduce the rate of false positive test results. If these results are confirmed by larger multicenter studies, the new AFS will represent a great improvement in fetal aneuploidy screening. (c) 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2008.

When excluding the maternal age from risk calculation, the detection of aneuploidies showed a shift from older to younger women. Overall, the detection rate did not change significantly. However, the false positive rate was 25% lower with the exclusion of maternal age.

Objectives

Currently available publications demonstrate a correlation between abnormal yolk sac size and miscarriage. However, in both cases a trisomy was confirmed. It should therefore be discussed whether form and size of the yolk sac could be a marker for chromosomal abnormalities of the fetus.

By means of the new AFS-3D method the same count of diseased fetuses was detected compared with prior screening tests. Simultaneously, expectant mothers were spared from unnecessary invasive diagnostics in 65 % of the cases. The choice of an altered cut-off or other volume shapes are feasible and should be examined in further studies.

First trimester screening would become reasonable in women over 40 years. However, women over 35 would also be more often affected by false-negative results. The implications of a concept adaptation should be analyzed in a large prospective study.

The calculation with AFS generated more precise risk estimations for trisomy 13, 18, and 21. An examination in large, prospective studies may be recommended to consider an introduction of this novel test strategy.

In this preliminary study, PRC demonstrated highly significant results in detecting aneuploidies in FTS. However, in comparison to JOY, its test performance was significantly inferior. A twice higher false positive rate would have doubled unnecessary invasive testing in a prospective setting. We therefore recommend a methodical revision of PRC.