Maternal serum PAPP-A concentrations at week 15 were significantly associated with a protective effect on the development of GDM by week 28 of pregnancy [odds ratio (OR) 0.623 (0.453, 0.856), P = 3.5 × 10−3, McFadden’s pseudo r2 = 1.7%, n = 777]. This evidence concerns the gene PAPPA and gestational diabetes.