title: Relationship of urinary phthalate metabolites with serum thyroid hormones in pregnant women and their newborns: a prospective birth cohort in Taiwan.
abstract: BACKGROUND
  The purpose of this study was to examine the relationship of phthalates exposure with thyroid function in pregnant women and their newborns.
  
  
  METHODS
  One 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.
  
  
  RESULTS
  Median 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 < 0.006, we found that urinary mono-benzyl phthalate (MBzP) levels were significantly and negatively associated with serum TSH in cord blood (β = -2.644, p = 0.003).
  
  
  CONCLUSIONS
  Maternal 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.
authors.affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Gynecology and Obstetrics, E-Da Hospital, Kaohsiung, Taiwan; School of Medicine, College of Medicine, I-Shou University, Kaohsiung, Taiwan.
authors.forename: Fu-Chen
authors.initials: FC
authors.lastname: Kuo
authors.affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Sheng-Wen
authors.initials: SW
authors.lastname: Su
authors.affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chia-Fang
authors.initials: CF
authors.lastname: Wu
authors.affiliation: Department of Nutrition, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Meng-Chuan
authors.initials: MC
authors.lastname: Huang
authors.affiliation: Department of Chemistry, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Jentaie
authors.initials: J
authors.lastname: Shiea
authors.affiliation: Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Bai-Hsiu
authors.initials: BH
authors.lastname: Chen
authors.affiliation: Department of Nuclear Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Chen
authors.affiliation: Department of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan; Center of Environmental and Occupational Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung, Taiwan; Department of Family Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Ming-Tsang
authors.initials: MT
authors.lastname: Wu
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010795:Phthalic Acids / Q000652:urine*; D011247:Pregnancy / Q000097:blood / Q000652:urine; D011263:Pregnancy Trimester, Third / Q000097:blood / Q000652:urine; D011446:Prospective Studies; D013624:Taiwan; D013963:Thyroid Hormones / Q000097:blood*
chemical_list: D010795:Phthalic Acids; D013963:Thyroid Hormones; C103325:mono-benzyl phthalate