To assess and compare the cost effectiveness of three different strategies for prenatal screening for Down's syndrome (integrated test, sequential screening, and contingent screenings) and to determine the most useful cut-off values for risk.
Centre de recherche du CHUQ, Service de Génétique Médicale, Unité de Diagnostic Prénatal, Faculté de Médecine, Université Laval, Québec city, Québec, Canada. jean.gekas@mail.chuq.qc.ca