Changing Attitudes towards Non-Invasive Aneuploidy Screening at Advanced Maternal Age in a German Tertiary Care Center - Geipel, A; Daiss, T; Katalinic, A; Germer, U; Kohl, T; Krapp, M; Gembruch, U; Berg, C (Ultraschall in der Medizin - European Journal of Ultrasound, 2007)