Objective To understand the fetal exposure concentrations to phthalic acid esters (PAEs) and assess the associations between PAEs concentrations and the levels of sex hormones or thyroid hormones in newborns.
Methods Linear regression models were used to assess the associations between PAEs metabolites in meconium samples and sex or thyroid hormones free testosterone (FT) and total thyroxine (T4) in cord blood samples.
Results The main metabolites in meconium were mono-2-ethylhexyl phthalate (MEHP), mono-n-butyl phthalate (MnBP), and monoisobutyl phthalate (MiBP), with detection rates of 100%, 99%, and 99%, respectively. Estradiol level in newborn boys was positively correlated to the concentrations monomethyl phthalate (MMP) (b=2.44, P=0.027), MnBP (b=4.08, P=0.044), and MiBP (b=3.89, P=0.003). FT in newborn boys was positively correlated to MEHP (b=4.42, P=0.049). None of PAEs metabolite concentrations was related to sex hormone level in newborn girls. Thyroid stimulating hormone (TSH) level in newborn boys was positively correlated to MEP concentration (b=0.40, P=0.015). No other associations between thyroid hormone levels and PAEs metabolite concentrations in meconium were found.
Conclusion Fetal exposure to PAEs may be associated with changes of sex hormone levels in newborns.
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