Metformin may be as safe as insulin during pregnancy, 11-year data shows

BOSTON—Metformin is safe to use during pregnancy to manage diabetes, with no long-term adverse effects on the children born and their mothers for at least 11 years after childbirth, according to research presented Sunday at ENDO 2024, the Endocrine Society’s annual meeting in Boston, Mass. This is the first study to look at longer term effects of metformin use during pregnancy.

“Metformin has been extensively used for managing raised blood glucose values in pregnancy for many decades now. It is the only blood glucose-lowering oral medication approved for use in pregnancy,” said Deep Dutta, M.D., D.M., Director of Endocrinology at CEDAR Superspeciality Healthcare in Dwarka, New Delhi, India.

The researchers cited that data are only available up to roughly five years after childbirth in most studies they found in their analysis. They sought to understand the longer-term effects on mothers with diabetes and their children beyond previously published data.

In their literature review, the researchers analyzed data from 10,117 children-mother pairs taken from seven different study cohorts.

Nine-year-old children born to mothers who took metformin during pregnancy showed similar BMI, waist circumference, dual-energy X-ray absorptiometry (DXA) total body fat, DXA-total body fat percent, DXA-total body fat-free mass, MRI visceral adipose tissue and magnetic-resonance spectroscopy liver fat percentage as children born to mothers who used insulin during pregnancy.

Ultimately, they concluded that taking metformin during pregnancy is as safe as using insulin for lowering blood glucose during pregnancy. Obesity and diabetes in mothers who took metformin during pregnancy were also similar during the 11-year postpartum follow-up period.

Dutta said that the rate of obesity, diabetes or motor development issues in these two groups of children was also similar until 11 years after childbirth.

“Our study provides us with reassuring data on the long-term safety of metformin use in pregnancy on the children and their mothers,” Dutta said.

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