Effects of single and combined exposure to lead and stress during pregnancy on offspring neurodevelopment

To assess associations of single and combined exposures to lead and stress during different stages of pregnancy with offspring neurodevelopment. We measured prenatal lead (maternal blood-lead in early-pregnancy and umbilical-cord-blood-lead) and maternal stress levels in Shanghai-Birth-Cohort from 2013 to 2016. Maternal stress was assessed using Center-for-Epidemiological-Studies-Depression-Scale and Self-Rating-Anxiety-Scale during mid-pregnancy. The Ages-Stages-Questionnaires-3 (at 6/12-months-of-age) and Bayley-III (at 24-months-of-age) were both used to assess neurodevelopment. A total of 2132 mother-child pairs with both prenatal lead and stress measurements were included. The geometric-means of blood-lead in early-pregnancy and cord-blood-lead were 1.46 μg/dL and 1.33 μg/dL, respectively. Among the study women, 1.89 % and 0.14 % were screened positive for depression and anxiety. Adjusting for related confounders, the combined exposures had stronger adverse associations with offspring social-emotional skills than single exposures; and the combined exposure in early-pregnancy was associated with greater neurodevelopmental differences than combined exposure around-birth, especially in social-emotion at 24 months-of-age [β (95 %CI): − 10.48(−17.42, −3.54) vs. − 5.95(−11.53, −0.36)]. Both single and combined prenatal exposures to lead/stress impaired infant neuro-development, and the effects of combined exposure may be more profound than single exposures. Combined exposure in early-pregnancy may be associated with worse neurodevelopmental outcomes than combined exposure around-birth, especially in social-emotional development. •Effects of prenatal single and combined exposure to lead and stress were investigated using a large-scale birth cohort.•The overall levels of prenatal exposures to lead/stress were relatively low in the Shanghai study women.•Adverse effects of prenatal combined exposure on offspring neurodevelopment may be more profound than single exposure.•The impaired neurodevelopment domains in the offspring mainly include social-emotional development.•Higher levels of impairments were induced when the combined exposure occurred in an earlier stage of pregnancy.