A Trial in Progress: Gestational Diabetes

Abstract

The Metformin in Gestational Diabetes (MiG) trial is a prospective randomized multicenter trial in women with gestational diabetes mellitus (GDM) that is testing the hypothesis that metformin treatment, compared with insulin, is associated with similar perinatal outcomes, improved markers of insulin sensitivity in the mother and baby, and improved treatment acceptability. Women with GDM who are at 20–33 weeks’ gestation in a singleton pregnancy and meet entry criteria are randomized to insulin or metformin treatment. The primary outcome is a composite of neonatal morbidity, with 750 recruits required. The trial finished recruiting in October 2006. Interim data on 200 women (and subsequently 550 women) have been reviewed by the data safety monitoring committee, which has reported that the trial should answer the hypotheses and no protocol changes are required. Data from 457 women show recruits are a mean age of 33.3 ± 5.3 years; BMI of 32.1 ± 7.8 kg/m2; and ethnicity 47.2% European/Caucasian, 25.7% Polynesian, and 24.3% Indian/Asian. The mean fasting glucose at recruitment is 5.3 ± 1.1 mmol/l and A1C is 5.7 ± 0.8%. Long-term follow-up of children started at age 2 years, with assessments of body composition, neurodevelopment, diet, and activity levels. The MiG trial will address the efficacy and detailed safety of metformin compared with insulin in women with GDM. Long-term follow-up of offspring will examine whether treatment influences later health (Australasian Clinical Trials Registry number 12605000311651). GDM is diagnosed in over 4% of pregnant women (1,2). The prevalence is increasing as the pregnancy population becomes older and fatter. Women with GDM have increased rates of pregnancy complications and risks of later type 2 diabetes (1,2). The offspring of women with GDM also have increased risks of perinatal complications and long-term risks of obesity and type 2 diabetes (1– …