Evidence is cumulating on the adverse health effects of environmental exposures on health of the fetus and the childbearing mothers. Among mother's conditions, gestational diabetes mellitus has been considered rarely in spite of its importance for both mother and child. We determined the role of maternal exposure to lead (Pb), cadmium (Cd) and manganese (Mn) to gestational diabetes mellitus (GDM) on diagnosed GDM and impaired glucose tolerance (IGT) in diabetes-free mothers from the French EDEN mother-child cohort. 623 pregnant women without pre-existing diabetes were included in the study. GDM and IGT were diagnosed by a gynecologist during consultations after blood analysis. Pb, Cd and Mn were measured in second-trimester blood samples. Associations between In-transformed concentrations of metals and GDM and IGT respectively were examined using multiple logistic regression analysis adjusted for potential confounders. The prevalences of GDM and IGT were 7.1% and 10.1% respectively. After adjustment for confounders, Cd was statistically related to having had a diagnosis of GDM or IGT (Adjusted Odds-Ratio (AOR): 1.61, 1.05-2.48), and Pb to GDM at borderline significance (AOR: 1.65, 0.82-3.34). Our findings add to the growing evidence supporting the role of maternal exposure to heavy toxic metals that persist longtime in the environment as a risk factor for GDM. (C) 2018 Elsevier B.V. All rights reserved.