Maternal body burden of cadmium and offspring size at birth

•Cadmium levels in the general population potentially adversely affect size at birth.•Maternal urinary cadmium was inversely related to birth length among female infants.•For male infants, maternal cadmium was positively associated with birth length.•Maternal cadmium was also inversely related to ponderal index among male infants.

Increasing evidence suggests an inverse association between cadmium (Cd) and size at birth, potentially greatest among female neonates. We evaluated whether greater maternal body burden of Cd is associated with reduced neonatal anthropometry (birthweight, birth length, head circumference, and ponderal index) and assessed whether these associations differ by infant sex. The analytic sample for the present study (n=396) was derived from a subcohort of 750 women randomly drawn from among all participants (N=4344) in the Omega Study, a prospective pregnancy cohort. Creatinine-corrected Cd in maternal clean-catch spot urine samples (U-Cd) was quantified by inductively coupled plasma mass spectrometry. Continuous log2-transformed Cd (log2-Cd) and U-Cd tertiles (low<0.29 μg/g creatinine, middle 0.29-0.42 μg/g creatinine, high≥0.43 μg/g creatinine) were used in multivariable linear regression models. Females had reduced birth length with greater U-Cd tertile, whereas males birth length marginally increased [β(95% CI) females: low=reference, middle=−0.59 cm (−1.37, 0.19), high=−0.83 cm (−1.69, 0.02), p-trend=0.08; males: low=reference, middle=0.18 cm (−0.59, 0.95), high=0.78 cm (-0.04, 1.60), p-trend=0.07; p for interaction=0.03]. The log2-Cd by infant sex interaction was statistically significant for ponderal index [p=0.003; β(95% CI): female=0.25 kg/m3 (−0.20, 0.70); male=−0.63 kg/m3 (−1.01, −0.24)] and birth length [p<0.001; β(95% CI): female=−0.47 cm (−0.74, −0.20), male=0.32 cm (0.00, 0.65)]. Our findings suggest potential sex-specific reversal of Cd's associations on birth length and contribute to the evidence suggesting Cd impairs fetal growth.