Меtformin-associated maternal and neonatal outcomes in women with gestational diabetes - a retrospective cohort study.

Objectives: To assess the maternal and neonatal outcomes in women with GDM treated with metformin, medical nutrition therapy (MNT) or insulin.
Material and Methods: The current retrospective cohort study includes data from 233 women diagnosed with GDM who gave birth between January 2017 and January 2019 at an obstetrics and gynecology hospital in Sofia, Bulgaria. Patients were assigned to three groups, according to the treatment approach - metformin group (n = 70), insulin group (n = 40), and MNT group (n = 123). Values of fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) have been evaluated at diagnosis of GDM and the third trimester of pregnancy. A comparative analysis of pregnancy outcomes and short-term neonatal characteristics in the investigated groups has been performed.
Results: Women indicated for pharmacological treatment (metformin or insulin) had significantly higher BMI (p < 0.01), FPG (p < 0.001), and HbA1c levels (p < 0.001) at baseline. However, during pregnancy, patients treated with metformin showed a significantly lower BMI (p < 0.01), FPG (p < 0.01), and HbA1c (p < 0.01). Neonates born to metformin-treated mothers had lower birth weight compared to those born to women in the MNT and insulin groups (metformin vs MNT, p < 0.001; metformin vs insulin, p = 0.03). The lowest incidence of newborns with macrosomia and neonatal hypoglycemia has been observed in the metformin cohort. Not a single newborn with an Apgar score under 7 has been identified in the metformin group.
Conclusions: According to the current analysis, women with GDM treated with metformin demonstrated better maternal and neonatal outcomes. No short-term complications in newborns have been associated with metformin use during pregnancy.