Millions of pregnant women use metformin, partly due to PCOS but most often to treat gestational diabetes. Few negative side effects have been demonstrated from its use, and none for the fetus.
The results show that 8-year-old children who were exposed to metformin in utero (in the womb) on average had a higher body mass index (BMI) and waist circumference compared to children of women in a control group.
Children born to mothers with PCOS but not exposed to metformin did not have elevated BMI, weight or height. These children, when measured as 8-year-olds, did have a larger waist circumference as compared to children with mothers who did not have PCOS, however. Larger waist circumference is associated with an unfavorable distribution of body fat which leads to obesity ailments.