Despite the clinical and scientific lines of evidence listed above, the Italian standards for the treatment of diabetes mellitus 2018 declare that in all women with GDM or T2DM in whom the glycemic target is not achievable by diet alone, insulin therapy should be promptly instituted; oral antidiabetics and non-insulin injection therapy are currently not recommended in pregnancy; a possible introduction of metformin into the GDM therapy remains suspended pending reliable data on its long-term safety in the fetus and offspring (71). Here, INS is linked to type 2 diabetes mellitus.