Taking metformin during pregnancy may put their children at increased risk of having obesity or overweight. The trend became apparent when children reached six months of age. At the age of four years, the children in the metformin group had higher BMI scores and were more likely to meet the criteria for obesity or overweight than children in the placebo group. The study is published online February 27, 2018 in the Journal of Clinical Endocrinology and Metabolism.