Effects of mid-pregnancy exposure to phthalate acid esters and polycyclic aromatic hydrocarbons on offspring size at birth

Abstract

BACKGROUND AND AIM: Phthalate acid esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) are the environmental endocrine disruptors and threaten human health especially for pregnant women and fetuses. Evidence on how these contaminants affect fetal growth in newborns is lacking and inconsistent. We therefore conducted a prospective cohort study to assess the associations of prenatal PAEs and PAHs exposure with fetal growth. METHODS: This study included 835 mother-infant pairs from the Tongji Birth Cohort in Wuhan, China. We detected the concentrations of 9 PAEs metabolites and 10 PAHs metabolites in urine samples collected during mid-pregnancy (13~28 weeks’ gestation). The fetal biometric parameters for head circumference (HC), abdominal circumference (AC), femur length (FL), and estimated fetal weight (EFW) were collected during pregnancy (weeks 28~37). We measured birth size. The associations of urinary metabolites with fetal growth parameters were estimated by using linear regression models. RESULTS:We observed each ln-unit increase in monoethyl phthalate (MEP) was associated with decrement in EFW (-128 g, 95% CI: -233, -23), birth weight (-44 g, 95% CI: -88, -1), birth weight z-scores (-0.10 SDs, 95% CI: -0.20, 0.00) among boys but not in girls. Elevated maternal 2-hydroxyfluorene concentrations were associated with the decline of birth length (-0.22 cm, 95% CI: -0.37, -0.07) and birth length z-scores (-0.12 SDs, 95% CI: -0.21, -0.04) in boys. However, we observed a positive association between 4-hydroxyphenanthrene and birth length z-scores in girls with a β = 0.11 SDs, (95% CI: 0.00, 0.21). Meanwhile, gestational levels of MEP, monoisobutyl phthalate, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 9-hydroxyphenanthrene, and 9- hydroxyfluorene were also positively associated with HC and AC in girls. CONCLUSIONS:This study suggested that the impact of mid-pregnancy PAEs and PAHs exposure on fetal and birth size maybe in a sex-specific manner and MEP was negatively associated with some fetal growth parameters among boys. More findings are required in future research. KEYWORDS: Phthalates, Multi-pollutant, Endocrine disrupting chemicals, Pregnancy outcomes