RENO, NEV. — Metformin controlled blood glucose levels as well as insulin in patients with class A2 gestational diabetes, and was not associated with any adverse maternal or neonatal outcomes, according to a randomized trial with 63 patients.
“We found that metformin appears to be an acceptable way to achieve glucose homeostasis in the A2 diabetes patient,” Christian Briery, M.D., said at the annual meeting of the Society for Maternal-Fetal Medicine.
The study enrolled pregnant patients who were at greater than 11 weeks' gestation but less than 35 weeks' gestation. The women received a starting dose of insulin of 0.7 U/kg daily, in three doses (31 patients) or 500 mg metformin twice daily (32 patients). The patients were then monitored weekly to see that they achieved a postprandial blood glucose level of less than 120 mg/dL and a fasting glucose level of 60–90 mg/dL, said Dr. Briery of the University of Mississippi Medical Center, Jackson.
In blood glucose measurements taken by the patients at home, the mean fasting glucose level was 96.8 mg/dL in the insulin-treated patients and 92.6 mg/dL in the metformin group.
Similarly, the mean postprandial glucose levels ranged in the insulin group from 104.4 mg/dL 2 hours after breakfast to 112.5 mg/dL 2 hours after lunch, while they ranged in the metformin group from 104.6 mg/dL 2 hours after breakfast to 108.1 mg/dL 2 hours after dinner.
The maternal and delivery measures considered included abdominal delivery, gestational age at delivery, shoulder dystocia, and postpartum hemorrhage. There was no difference in those measures between the groups. There was one intrauterine fetal death in the metformin group from a “cord problem” that was determined not to be related to treatment because the mother's glucose levels were consistently normal, Dr. Briery said.
Neonatal outcomes that were considered include birth weight, 5-minute Apgar score, respiratory distress syndrome, neonatal hypoglycemia, and neonatal ICU admission. Again, there was no difference in the groups.
A previous study of metformin use in pregnancy looked specifically at patients with polycystic ovary syndrome, who conceived while on the drug, and it likewise found no indication of any adverse effects that might be associated with the agent.