Research shows that the oral diabetes medications metformin and glyburide are not as effective as insulin at reducing the number of babies born who are large for their gestational age.
In addition, the University of Amsterdam-led study showed more cases of hypoglycemia in women treated with the oral medications versus insulin.
Up to 10% of pregnant women in the U.S. develop gestational diabetes at some point during their pregnancy. While the condition usually resolves after giving birth, women with this condition are at significantly increased risk of developing type 2 diabetes and may experience diabetic complication during pregnancy such as extreme low blood glucose, or hypoglycemia, after treatment.
The condition can also negatively impact infant health with babies typically being born abnormally large, being susceptible to jaundice and being at increased risk for type 2 diabetes and obesity as they grow up.
“Insulin has conventionally been used as the primary pharmacological agent for treatment of gestational diabetes and has been demonstrated to improve perinatal outcomes in persons … who fail to maintain adequate glucose control with diet alone,” wrote Doortje Rademaker, MD, Amsterdam Reproduction and Development Research Institute, Amsterdam University Medical Centers, and colleagues in JAMA.
However, “in the last two decades, oral glucose-lowering agents such as metformin and glyburide (glibenclamide) have emerged as potential alternatives to insulin treatment for gestational diabetes and preexisting diabetes as they are easier to administer, less costly, and have better acceptance among patients.”
This study sought to compare the two treatment pathways and assess whether or not the oral agents were as effective as insulin at preventing unwanted outcomes.
Overall, 820 women with gestational diabetes between 16 and 34 weeks of gestation were enrolled. The results showed that the percentage of large for gestational age babies in women treated with oral anti-diabetes medication was 23.9% versus 19.9% in those randomized to insulin.
In those treated with oral medication, 79% maintained good control of their blood sugar without needing insulin, but more women in this group (20.9%) reported hypoglycemia compared with 10.9% in the insulin group.
“Treatment of gestational diabetes with metformin and additional glyburide, if needed, did not meet criteria for noninferiority compared with insulin with respect to the proportion of infants born large for gestational age,” conclude the authors.
“While our overall results do indicate limitations of treatment intensification of metformin with glyburide, the results of the exploratory analysis of those treated with metformin alone are in agreement with a recent meta-analysis supporting metformin as first-line pharmacological treatment of gestational diabetes,” they concede.
