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.

缩写说明：ADHD（attention deficit hyperactivity disorder，注意缺陷多动障碍）、PFOS（perfluorooctane sulfonate，全氟辛烷磺酸）、PFOA（perfluorooctanoic acid，全氟辛酸）、Parity（孕次，即既往妊娠次数）。
a 芬兰、丹麦与挪威。
b 西欧及前东欧地区。
c 体重指数依据世界卫生组织的标准值进行分类。
d 产妇吸烟情况以脐带血清中可替宁的实测浓度为判定依据。