title: Early Phthalates Exposure in Pregnant Women Is Associated with Alteration of Thyroid Hormones.
abstract: BACKGROUND
  Previous studies revealed that phthalate exposure could alter thyroid hormones during the last trimester of pregnancy. However, thyroid hormones are crucial for fetal development during the first trimester. We aimed to clarify the effect of phthalate exposure on thyroid hormones during early pregnancy.
  
  
  METHODS
  We recruited 97 pregnant women who were offered an amniocentesis during the early trimester from an obstetrics clinic in southern Taiwan from 2013 to 2014. After signing an informed consent form, we collected amniotic fluid and urine samples from pregnant women to analyze 11 metabolites, including mono-ethyl phthalate (MEP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-(2-ethylhexyl) phthalate (MEHP), mono-butyl phthalate (MnBP), of 9 phthalates using liquid chromatography/ tandem mass spectrometry. We collected blood samples from each subject to analyze serum thyroid hormones including thyroxine (T4), free T4, and thyroid-binding globulin (TBG).
  
  
  RESULTS
  Three phthalate metabolites were discovered to be >80% in the urine samples of the pregnant women: MEP (88%), MnBP (81%) and MECPP (86%). Median MnBP and MECPP levels in pregnant Taiwanese women were 21.5 and 17.6 μg/g-creatinine, respectively, that decreased after the 2011 Taiwan DEHP scandal. Results of principal component analysis suggested two major sources (DEHP and other phthalates) of phthalates exposure in pregnant women. After adjusting for age, gestational age, TBG, urinary creatinine, and other phthalate metabolites, we found a significantly negative association between urinary MnBP levels and serum T4 (β = -5.41; p-value = 0.012; n = 97) in pregnant women using Bonferroni correction.
  
  
  CONCLUSIONS
  We observed a potential change in the thyroid hormones of pregnant women during early pregnancy after DnBP exposure. Additional study is necessitated to clarify these associations.
authors.affiliation: National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan.|Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Po-Chin
authors.initials: PC
authors.lastname: Huang
authors.affiliation: National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan.
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Tsai
authors.affiliation: National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan.
authors.forename: Wei-Yen
authors.initials: WY
authors.lastname: Liang
authors.affiliation: National Environmental Health Research Center, National Institute of Environmental Health Sciences, National Health Research Institutes, Miaoli, Taiwan.
authors.forename: Sih-Syuan
authors.initials: SS
authors.lastname: Li
authors.affiliation: School of Public Health, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Han-Bin
authors.initials: HB
authors.lastname: Huang
authors.affiliation: Department of Obstetric and Gynecology, National Cheng Kung University Hospital and College of Medicine, Tainan, Taiwan.
authors.forename: Pao-Lin
authors.initials: PL
authors.lastname: Kuo
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism; D015415:Biomarkers; D003404:Creatinine / Q000097:blood; D052244:Endocrine Disruptors; D004781:Environmental Exposure; D005260:Female; D005865:Gestational Age; D006801:Humans; D018811:Maternal Exposure; D008572:Menarche; D055432:Metabolomics; D010795:Phthalic Acids / Q000009:adverse effects; D011247:Pregnancy; D062486:Public Health Surveillance; D013963:Thyroid Hormones / Q000097:blood*
chemical_list: D015415:Biomarkers; D052244:Endocrine Disruptors; D010795:Phthalic Acids; D013963:Thyroid Hormones; C032279:phthalic acid; D003404:Creatinine