Association of umbilical cord blood phthalate levels with neonatal growth parameters in term pregnancies

BACKGROUND: Prenatal exposure to endocrine-disrupting chemicals (EDCs), including di(2-ethylhexyl) phthalate (DEHP) and bisphenol A (BPA), has been associated with altered fetal growth. Umbilical cord blood provides a direct indicator of fetal exposure and may offer advantages over maternal urinary biomarkers. OBJECTIVE: To examine the associations between cord blood concentrations of DEHP metabolites and BPA and neonatal anthropometric measures in term pregnancies. METHODS: This cross-sectional study included 84 singleton term mother–infant pairs. Cord blood DEHP metabolites and BPA were quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Birth weight, length, and head circumference were measured at delivery and expressed as sex- and gestational age–adjusted z-scores. Multivariable linear regression models adjusted for maternal age, pre-pregnancy body mass index, parity, smoking status, infant sex, gestational age and maternal occupation were applied. Exposure–response patterns were further explored using quartile-based analyses and restricted cubic spline models. RESULTS: DEHP metabolites were detected in 92.0% and BPA in 90.4% of cord blood samples. Higher ΣDEHP concentrations were associated with lower birth weight (β = − 0.24 SD), birth length (β = − 0.15 SD), and head circumference (β = − 0.11 SD; all p < 0.05). BPA exhibited a non-linear, threshold-type association, as confirmed by restricted cubic spline analyses, with lower birth weight and length observed only at higher exposure levels. No significant sex-specific interactions were identified. CONCLUSION: Higher prenatal DEHP exposure, assessed using umbilical cord blood, was associated with modest yet consistent differences in neonatal growth parameters among term infants, whereas BPA demonstrated weaker and non-linear associations. These findings should be interpreted within an observational framework and do not imply causality. These findings underscore the relevance of prenatal exposure to common endocrine-disrupting chemicals for early human growth.