Women who develop gestational diabetes mellitus (GDM) have a high risk of developing type 2 diabetes later in life. Treatment with metformin may prevent or delay the development of diabetes in these women, a new study suggests, although intensive lifestyle interventions proved equally effective.

The study included 350 women with a history of GDM and 1,416 women who'd given birth to at least one child and had no history of GDM. They were randomly assigned to receive standard lifestyle intervention and placebo, metformin therapy, or intensive lifestyle intervention. All women had similar glucose levels at the start of the study.

Following the women for 3 years, researchers found that those with a history of GDM on placebo therapy had a 71% increased incidence of diabetes compared with women with no history of GDM. Among women with a history of GDM, both metformin therapy and intensive lifestyle intervention reduced risk by about 50%, compared with the placebo group.

For women who'd never had GDM, metformin therapy decreased the incidence of diabetes by 14%, but intensive lifestyle intervention reduced their risk by 49%.

Researchers concluded that both intensive lifestyle intervention and metformin are "highly effective" in delaying or preventing diabetes in women with impaired glucose tolerance and a history of GDM.

Source: Ratner RE, Christophi CA, Metzger BE, et al. Prevention of diabetes in women with a history of gestational diabetes: effects of metformin and lifestyle interventions. J Clin Endocrinol Metab. 2008;93(12):4774-4779.