Unfortunately, despite the association with GDM and gonadotropin secretion [54], insulin-like growth factors (particularly IGF-1) were not assessed in our study because their measurements in urine require acidification, while IGF-1 (and probably also other insulin-like growth factors) detectable in saliva is locally produced, and the salivary concentrations do not correlate with plasma levels [55]. This evidence concerns the gene IGF1 and gestational diabetes.