Examination of a first-trimester Down syndrome screening concept on a mix of 11,107 high- and low-risk patients at a private center for prenatal medicine in Germany.

Objective: To assess the performance of a combined first-trimester screening concept for trisomies 21, 18 and 13 applied to a low- and high-risk patient sample in a specialized private center for prenatal medicine.

Study Design: The quality of different first-trimester screening algorithms (risk calculation based on maternal age and nuchal translucency alone, maternal age and serum parameters (free beta-hCG and PAPP-A) alone and a combination of both) was evaluated in a study population of low- and high-risk cases for fetal aneuploidies. All measurements were performed between the 11th+0 and 13th+6 weeks of gestation during the study period from November 2000 to December 2006, in accordance with the guidelines of the Fetal Medicine Foundation (FMF), London.