Fig. 1

Model-based dose–response relationships between maternal B-Pb levels and birth weight (a), head circumference (b) and crown–heel length (c) fitted using multivariable fractional polynomials (mfp) and lowess smoothing curves. The mfp models were adjusted for maternal educational attainment, smoking, gestational age (centred at 40 weeks), maternal height and pre-pregnancy weight, and sex of the infant. a Birth weight, b head circumference, c crown–heel length