10 days after the switch to GDM we observed a substantial reduction of NESTIN+ and NG2+ precursors, and the appearance/increase of A2B5+ glial progenitors (≈20%), oligodendroglial progenitors/immature oligodendrocytes (Olig2+ and O4+ cells; ≈10% and ≈3%, respectively) and mature oligodendrocytes (APC+ and CNPase+ cells; ≈10% and ≈20%, respectively). This evidence concerns the gene OLIG2 and gestational diabetes.