Median concentration (in nanograms/milliliters) of perfluorinated compounds by the maternal and infant demographic characteristics.

Abbreviations: ADHD, attention deficit hyperactivity disorder; PFOS, perfluorooctane sulfonate; PFOA, perfluorooctanoic acid; Parity, number of previous pregnancies.aFinland, Denmark, and Norway.bWestern Europe and former Eastern Europe.cBody mass index was classified according to the standard values of the World Health Organization.dMaternal smoking is based on measured cotinine concentrations in the umbilical cord serum.