Metformin in pregnancy linked to child obesity

Taking the common type 2 diabetes drug metformin during pregnancy has been linked to an increased risk of the child becoming overweight or obese.
Metformin, a blood glucose-lowering drug, may be given to pregnant women who have gestational diabetes or polycystic ovary syndrome (PCOS). Treatment recommendations vary across different countries and in the UK, metformin is not routinely recommended for treating PCOS.
It is thought around 10% of women suffer from PCOS which can cause infertility and is linked with increased risk of developing type 2 diabetes.
In a Norwegian study, researchers identified that children exposed to metformin in utero had a higher average weight aged four compared to children not exposed. The findings indicate a link rather than causatio, however.
In the study, women with PCOS were randomised to daily metformin or placebo. The children of these women were then followed up, with complete health data available for 154 children.
Birth weight seemed unaffected but then became more apparent as the babies reached the six-month stage. The children were monitored at the age of four, when those exposed to metformin were heavier on average and more likely to be overweight or obese.
The researchers will also monitor the children in the future when they turn eight to see if the weight trend has continued.
The study’s first author, Dr Liv Guro Engen Hanem, from the Norwegian University of Science and Technology in Trondheim, said: “The results were surprising, since limited past research in this area had suggested metformin would have a protective effect on the children’s metabolic health.”
Dr Hanem added: “Few studies have examined the long-term health of children born to women with PCOS who took metformin. Our findings indicate more research is needed to determine its effects on children who were exposed in the womb.”
The findings appear online in the Journal of Clinical Endocrinology &Metabolism.