Abstract
Objective To compare the safety and tolerability of metformin to insulin for glycemic control
among women with preexisting type 2 and early A2 gestational diabetes.
Study Design Women with preexisting type 2 diabetes and those diagnosed with gestational diabetes
who required medical management prior to 20 weeks were randomly assigned to metformin
or insulin. Glycemic control, defined as >50% capillary blood glucose within target
range, was compared between groups. Other outcomes included patient tolerance, neonatal
and obstetric complications, maternal weight gain, neonatal cord blood C-peptide,
and patient satisfaction with therapy.
Results Twenty-eight women completed the study, with 14 in each group. Of the 15 women assigned
to metformin, 100% continued to receive metformin until delivery, although 43% required
supplemental insulin to achieve glycemic control. Glucose measures did not differ
between the groups, and the proportion who met fasting and postprandial glycemic target
values did not differ between the groups. Women treated with metformin had significantly
fewer subjective episodes of hypoglycemia compared with those using insulin (0% versus
36%; p = 0.04) as well as reported glucose values < 60 mg/dL (7.1% versus 50%; p = 0.03).
Conclusion Metformin should be considered for treatment of overt diabetes and early A2 gestational
diabetes in pregnancy.
Keywords
pregnancy - diabetes - metformin - randomized
