A previous trial showed that metformin used to treat gestational diabetes was not associated with perinatal complications and was more acceptable than insulin therapy to women, Dr. Hilkka Ijas, at Oulu University Hospital, and colleagues explain. “The aim of our study was to investigate the efficacy of metformin in the prevention of fetal macrosomy and its influence on neonatal morbidity,” they state.
The trial involved 100 women with gestational diabetes confirmed at a mean of 23 weeks gestation and whose glucose levels were not normalized with diet. They were randomized to insulin or metformin therapy at 30 weeks gestation. The main outcome was the incidence of large-for-gestational-age (LGA) infants and neonatal morbidity.
The rate of LGA was 8.5% in the insulin group and 10.0% in the metformin group, a nonsignificant difference (p=0.97), according to the report. Corresponding rates of neonatal hyperbilirubinemia were 36.0% vs 27.7% (p=0.38), and rates of NICU use were 22.0% and 14.9% (p=0.37), respectively.
“Fifteen out of 47 (31.9%) women randomised to metformin therapy did not reach normoglycaemia, and needed supplemental insulin,” the authors report. These women had greater BMIs, higher fasting glucose concentrations and earlier need for pharmacological treatment than women who were normoglycemic with metformin.
“We conclude that metformin seems to be a safe and effective alternative to insulin in the treatment of gestational diabetes mellitus, and that it is especially suitable for women with mild gestational diabetes mellitus,” Dr. Ijas and colleagues write. “In cases with severe disease, determined by early diagnosis, fasting hyperglycaemia and significant obesity, promptly initiated insulin treatment seems to be a more optimal choice.”