Relationship of Urinary Phthalate Metabolites with Serum Thyroid Hormones in Pregnant Women and Their Newborns: A Prospective Birth Cohort in Taiwan

BackgroundThe purpose of this study was to examine the relationship of phthalates exposure with thyroid function in pregnant women and their newborns.MethodsOne hundred and forty-eight Taiwanese maternal and infant pairs were recruited from E-Da hospital in southern Taiwan between 2009 and 2010 for analysis. One-spot urine samples and blood samples in the third trimester of pregnant women and their cord blood samples at delivery were collected. Nine phthalate metabolites in urine were determined by triple quadrupole liquid chromatography tandem mass spectrometry, whereas serum from pregnant women and their cord blood were used to measure thyroid profiles (thyroid-stimulating hormone [TSH], thyroxine, free thyroxine, and triiodothyronine) by radioimmunoassay.ResultsMedian levels of urinary mono-n-butyl phthalate, mono-ethyl phthalate, and mono-(2-ethyl-5-oxohexyl) phthalate (μg/g creatinine) were the three highest phthalate metabolites, which were 37.81, 34.51, and 21.73, respectively. Using Bonferroni correction at a significance of ConclusionsMaternal urinary MBzP, of which the parental compound is butylbenzyl phthalate, may affect TSH activity in newborns. The alteration of thyroid homeostasis by certain phthalates in the early life, a critical period for neurodevelopment, is an urgent concern.背景：本研究旨在探讨邻苯二甲酸酯（phthalates）暴露与孕妇及其新生儿甲状腺功能之间的关联。 方法：本研究于2009至2010年间，从中国台湾南部的义大（E-Da）医院招募148对台湾母婴对开展分析。采集孕妇妊娠晚期的单次尿液样本与血液样本，以及分娩时的脐带血样本。采用三重四极杆液相色谱-串联质谱法测定尿液中的9种邻苯二甲酸酯代谢物；通过孕妇及新生儿的血清样本，采用放射免疫法检测甲状腺相关指标，包括促甲状腺激素（thyroid-stimulating hormone, TSH）、甲状腺素、游离甲状腺素及三碘甲状腺原氨酸。 结果：尿液中邻苯二甲酸单丁酯（mono-n-butyl phthalate）、邻苯二甲酸单乙酯（mono-ethyl phthalate）及邻苯二甲酸单-(2-乙基-5-氧代己基)酯（mono-(2-ethyl-5-oxohexyl) phthalate）的中位浓度（以μg/g肌酐计）位列所有检测代谢物前三，分别为37.81、34.51及21.73。采用Bonferroni校正法进行显著性检验。 结论：母体尿液中的邻苯二甲酸单苄酯（MBzP，其前体化合物为邻苯二甲酸丁苄酯）可能会影响新生儿的促甲状腺激素活性。在神经发育的关键早期生命阶段，部分邻苯二甲酸酯会干扰甲状腺稳态，这一问题亟待关注。