Objective: To investigate whether maternal serum pregnancy associated plasma protein-A (PAPP-A), total β human chorionic gonadotropin (hCG) levels and nuchal translucency (NT) measurements differ in women with pre-gestational diabetes mellitus (PGDM) compared to non-diabetic controls and to assess whether correction factors are needed for diabetic women in calculation of aneuploidy risks. This evidence concerns the gene PAPPA and gestational diabetes.