DESIGN AND PURPOSE: The supplemental administration of myo-inositol, Dchiro-inositol, folic acid and manganese (MDFM) was tested in a prospective, randomized, doubleblind, placebo controlled clinical trial, pilot study, to test the hypothesis that its supplemental administration in the second trimester of pregnancy would improve glucose and glycemic parameters and blood pressure. SUBJECTS AND METHODS: Non-obese uniparous healthy pregnant women between 13th and 24th week of pregnancy were divided into two groups: group I, control group with placebo, and the group II, women in treatment with myoinositol, D-chiro-inositol, folic acid and manganese. The main outcome measures were the comparative analysis of the parameters analyzed at time 0, after 30 days and 60 days; secondary outcome measure was the overall analysis of investigated parameters. RESULTS: 24 women were allocated to receive MDFM and 24 the placebo. The two groups did not significantly differ for demographic, lipidic and glycemic parameter and blood pressure. After 30 days, significantly lower cholesterol (p = 0.0001), significantly lower LDL (p = 0.0013), lower TG (p < 0.0001) and lower glycemia (p = 0.0021) were observed all favoring group II. No significant difference was observed for HDL, diastolic and systolic blood pressure. After 60 days, significant difference was observed for cholesterol (p = 0.0001), LDL (p = 0.0001), HDL (p = 0.0001), TG (p = 0.0001), glycemia (p = 0.0064), all favoring the group treated with MDFM. No significant differences were observed for systolic (p = 0.12) and diastolic blood pressure (p = 0.42). When examining for overall differences between the two groups, a significant difference was observed for examined parameters at time 0 and at time 60; cholesterol (p = 0.0001), LDL (p = 0.0001), HDL (p = 0.047), TG (p = 0.0001) and glycemia (p = 0.019) were reduced in the MDFM group. A significant reduction was also observed in group II for systolic blood pressure after 60 days of intervention (p = 0.0092), but not for diastolic blood pressure (p = 0.29). CONCLUSIONS: MDFM administration after 30 days in pregnancy improved glycemic and lipidic parameters, with significant gain after 60 days, without affecting diastolic blood pressure levels.