(a) L-WQS in boys, (b) time-varying differences between boys and girls, (c) time-varying weights of metal(loid) mixture in boys, (d) time-varying weights of metal-mixture in girls. We observed an inverse association between eGFR and metal(loid) mixture at 8–16 weeks before birth and from 15 weeks postnatally in boys (3a). This association was primarily driven by Li, Cr and As in the prenatal window, and Pb and Cd in the postnatal window (3c). The differences in effect estimates between sexes was greatest after 24 weeks postnatally (3b), but this was not statistically significant.