Metformin doesn’t affect fat distribution in mother or baby

In part of the EMPOWaR study, Tommy’s researchers found that taking metformin during pregnancy doesn’t change how fat is stored in the babies of obese women.
  • Author's list

    Professor Jane Norman, Carolyn Chiswick, Scott Semple

This research study is now complete

This study was part of the EMPOWaR study, which looked at whether taking a drug called metformin during pregnancy makes it less likely for obese women to have babies with a very high birth weight. Tommy's researchers used magnetic resonance imaging (MRI) to look at the effect of metformin on the body composition and fat distribution of mothers during pregnancy, and the fat distribution in the newborn baby.

In total, 37 women had MRI scans at both 28 and 36 weeks of pregnancy, and another 20 women had one or the other of these scans. Half of the women took metformin during pregnancy, while the other half took a placebo. We found that the distribution of fat in mothers and babies was similar regardless of whether they took metformin. Metformin also didn't lower the amount of harmful fat in liver and muscle.

Metformin does not prevent high birth-weight

This means that there may be no benefit to giving metformin to severely obese women during pregnancy. It is important to show this, so that these women are not given metformin in the belief that it may help. In the future we hope to follow up the babies, to see whether metformin during pregnancy has any long-term benefits on the babies' health.



Research papers

Carolyn Chiswick, Rebecca M Reynolds et al (2015) Effect of metformin on maternal and fetal outcomes in obese pregnant women (EMPOWaR): a randomised, double-blind, placebo-controlled trial. Lancet Diabetes Endocrinol. 2015 Oct; 3(10): 778–786. doi:  [10.1016/S2213-8587(15)00219-3]

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This study took place in a Tommy's centre and was funded by Tommy's, the Medical Research Council and the National Institute for Health Research