Myo-Inositol is an insulin sensitizing agent that ameliorate the insulin resistance in women affected by gestational diabetes (GDM), but there is no information about the effect on the glucose profile. Maternal hyperglycemia of GDM, especially hypoglycemic excursions, are associated with adverse pregnancy outcome. Continuous Glucose Monitoring System (CGMS) is obviously better than intermittent self monitoring in detecting glucose profile and magnitude and duration of glucose fluctuations. For this reason, we propose a clinical trial to analyze the characteristics of glucose variability in GDM women,treated with diet and folic acid alone or with diet, folic acid and myo-inositol supplementation.