Ethnic differences in the impact of gestational diabetes on macrosomia

Previous studies reported an ethnic disparity in gestational diabetes mellitus-associated birth outcomes, with some suggesting that macrosomia increases to a lesser extent in groups at high risk, the opposite of the pattern observed by others. Our aim was to evaluate ethnic variation in the impact of gestational diabetes mellitus (GDM).

A case-control study evaluating pregnancy outcomes was conducted in women with and without GDM from five ethnic groups. Data on GDM were collected between January 2004 and July 2017. Women giving birth between May 2013 and July 2017 in whom pre-existing diabetes had been ruled out served as controls. A multivariate logistic regression analysis was performed to determine factors independently associated with macrosomia.

Overall, 852 GDM women and 3,803 controls were included. In Caucasian and East-Asian women excessive gestational weight gain (OR 2.273, 95% CI 1.364-3.788 and OR 3.776, 95% CI 0.958-14.886) was an independent predictor of macrosomia. In Latin-American and Moroccan women, obesity (OR 1.774, 95% CI 1.219-2.581 and OR 1.656, 95% CI 1.054-2.601), GDM (OR 2.440; 95% CI 1.048-5.679 and OR 3.249, 95% CI 1.269-8.321) and gestational weight gain but only for Latin-American women (OR 2.365, 95% CI 1.039-5.384) were associated with macrosomia. In South-Central Asian women, only GDM was associated with macrosomia (OR 3.701, 95% CI 1.437-9.532).

GDM is an independent predictor of macrosomia in Latin-American, South-Central Asian and Moroccan women but not in Caucasian or East-Asian women in whom other factors play a more important role.