Both studies suggest that elevated leptin concentrations in early pregnancy may be a strong predictor of common high-risk obstetric situations and that a positive linear association exists between increase in leptin and risk of GDM and preeclampsia. However, compared to our study on obese women, they also included normal weight women, and all participants in our study had leptin concentrations above 31.0 ng ml−1, which were the highest tertile in the study of Qiu et al. It would be of further interest to investigate whether this association is consistent among obese women and whether changes in leptin concentration altered by gestational weight gain could influence the relative risks of GDM and preeclampsia.