Prenatal exposure to hexachlorobenzene (HCB) and reproductive effects in a multicentre birth cohort in Spain

To investigate the possible association between birth size or gestational length and maternal serum concentrations of hexachlorobenzene (HCB) in a population exposed to background levels. A total of 1568 mother–child pairs recruited in three Spanish areas (INMA Project) from 2004 to 2008 participated in the study. Multivariate analysis was performed between birth weight and length, weeks of gestation, preterm birth or small for gestational age and HCB concentrations in maternal serum. The median concentration of HCB was 45.45ng/g lipids. No association was found between HCB exposure levels and birth weight (β: −50.42 [−109.88; 9.04]), birth length (β: −0.07 [−0.32; 0.18]), gestation age (HR: 1.07 [0.94; 1.22]), small for gestational age (OR: 0.95 [0.56; 1.61]) and preterm birth (OR: 0.60 [0.29; 1.28]). Results remain similar after adjustment for other organochlorines. Our findings support the idea that exposure to low levels of HCB does not affect the intrauterine growth nor the duration of gestation. •This is a birth cohort study carried out in three different areas of Spain.•The median concentration of HCB in maternal serum was 45.45ng/g lipids.•HCB levels in maternal serum are not associated with birth size.•HCB levels in maternal serum are not associated with gestational length.