: 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.