Role of pregravid diet and metformin in the prophylaxis of gestational diabetes and its complications

The aim of this study was to improve the method for diagnosing insulin resistance (IR) and to assess the effect of pregravid diet alone or dietary supplementation in combination with metformin on the development of gestational diabetes mellitus (GDM) and its complications in patients with pre-diabetes. At the first stage of the study, glucose level was determined in the capillary blood of 61 women and, in the second stage, in the venous blood plasma of 60 individuals. The 75 g oral glucose tolerance test was performed in all patients. Plasma insulin level and IR index were determined basal (HOMA-IR) and two hours after the glucose load. The presence of IR was found in 68 women. All of them were treated with a diet, with 34 patients additionally treated with metformin at a dose of 1500 mg per day. The duration of therapy was 3–6 months.

It has been shown that the evaluation of IR index two hours after the glucose load significantly (p < 0.05) increases the diagnosis of the IR status, as in 56.5% of women with IR, the fasting IR (HOMA-IR) values were normal. The use of metformin combined with diet therapy in patients with IR, with easily assimilated carbohydrates excluded at the pregravid stage, is accompanied by a more significant loss of body weight with the achievement of a normal body mass index for pregnancy, when compared to diet therapy alone. In patients with IR after pregravid treatment with diet or diet with metformin, the frequency of obstetric complications, as well as of gestational diabetes mellitus, is comparable with that in normal women. In addition, such pregravid treatment protects patiens with IR from superfluous weight gain and fetal macrosomia.