The present study investigates the polymorphisms rs8050136, rs9939609, and rs1421085 of the FTO gene in women with gestational diabetes and their associations with maternal pre-pregnancy weight and BMI, gestational weight gain and mediators of insulin resistance in GDM like leptin, adiponectin, ghrelin and tumor necrosis factor-alpha (TNF-alpha), compared with healthy pregnant controls. This evidence concerns the gene GHRL and Insulin resistance.