Characterization of trace elements exposure in pregnant women in the United States, NHANES 1999-2016.

•Pregnant women in the U.S. are exposed to several trace elements simultaneously.•A majority of metal concentrations were higher in pregnant women compared to non-pregnant women.•Blood lead, cadmium, mercury, as well as urine antimony, cadmium and lead in women of childbearing age decreased over time.•Urine cobalt in women of childbearing age increased over time.