By: 31 July 2015
Obesity drug has no effect on birth weight

Obesity drug has no effect on birth weight

Treating pregnant women suffering from obesity with a diabetes drug does not stop their babies from being born overweight, a study has found.

The children of obese pregnant women face a lifetime of long-term health complications as they grow up according to the results of an EMPOWaR study that emphasises the importance for women to be of normal weight before pregnancy.

Researchers tested whether treating overweight mothers-to-be with the diabetes drug metformin – which helps to regulate blood sugar – would reduce the weight of their babies.

They treated 226 pregnant women suffering from obesity with the medication from the second trimester until their babies were born, but found that there was no difference in the weight of babies born to mothers who received the treatment compared with a group of 223 women who received a placebo.

Metformin also had no effect on the number of birth complications, such as miscarriages and still births.

The treatment did help to reduce blood sugar levels in the mothers-to-be. It also helped to lower the levels of other markers that have been linked to pre-eclampsia and premature births.

“We must find ways to encourage women to manage their weight before they become pregnant to minimise the potential adverse impact on their children,” said Jane Brewin, chief executive at Tommy’s. “This study shows us there are no easy answers and we must re-double our efforts to find effective ways to help women who are overweight in pregnancy.”

Researchers will need to follow the babies involved in the study for longer to determine whether the treatment lowers their chances of developing other health problems in later life.

The study was led by the University of Edinburgh in collaboration with the Universities of Warwick and Sheffield, and Liverpool. It is published in The Lancet Diabetes and Endocrinology.


Chiswick, C., Reynolds, R.M., Denison, F. (2015) Effect of metformin on maternal and fetal outcomes in obese pregnant women (EMPOWaR): a randomised, double-blind, placebo-controlled trial. The Lancet Diabetes & Endocrinology. doi:

Source: University of Edinburgh