title: Perchlorate and thiocyanate exposure and thyroid function in first-trimester pregnant women from Greece.
abstract: OBJECTIVE
  Thyroid hormone, requiring adequate maternal iodine intake, is critical for neurodevelopment in utero. Perchlorate and, less so, thiocyanate decrease uptake of iodine into the thyroid gland by competitively inhibiting the sodium/iodide symporter (NIS). It remains unclear whether environmental perchlorate exposure adversely affects thyroid function in first-trimester pregnant women.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  134 pregnant women from Athens, Greece, at mean ± SD 10·9 ± 2·3 weeks' gestation.
  
  
  METHODS
  Urinary iodide, perchlorate, and thiocyanate and thyroid function tests were measured.
  
  
  RESULTS
  The median urinary iodide was 120 μg/l. Urinary perchlorate levels were detectable in all women: median (range) 4·1 (0·2-118·5) μg/l. Serum thyroperoxidase antibodies (TPO Ab) were detectable in 16% of women. Using Spearman's rank correlation analyses, there was no correlation between urinary perchlorate concentrations and serum TSH, although inverse correlations were seen between urine perchlorate and free T3 and free T4 values. In univariate analyses, urine thiocyanate was positively correlated with serum TSH, but was not associated with serum free T3 or free T4. Urine perchlorate was positively correlated with gestational age. In multivariate analyses adjusting for urinary iodide concentrations, urine thiocyanate, gestational age, maternal age and TPO Ab titres, urine perchlorate was not a significant predictor of thyroid function.
  
  
  CONCLUSIONS
  Low-level perchlorate and thiocyanate exposure is ubiquitous, but, in adjusted analyses, is not associated with alterations in thyroid function tests among mildly iodine-deficient Greek women in the first trimester of pregnancy.
authors.affiliation: Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine, Boston, MA, USA. elizabeth.pearce@bmc.org
authors.forename: Elizabeth N
authors.initials: EN
authors.lastname: Pearce
authors.forename: Maria
authors.initials: M
authors.lastname: Alexiou
authors.forename: Eftychia
authors.initials: E
authors.lastname: Koukkou
authors.forename: Lewis E
authors.initials: LE
authors.lastname: Braverman
authors.forename: Xuemei
authors.initials: X
authors.lastname: He
authors.forename: Ioannis
authors.initials: I
authors.lastname: Ilias
authors.forename: Maria
authors.initials: M
authors.lastname: Alevizaki
authors.forename: Kostas B
authors.initials: KB
authors.lastname: Markou
mesh_terms: D000328:Adult; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D047109:Fetal Development / Q000187:drug effects; D006115:Greece; D006801:Humans; D007454:Iodides / Q000652:urine; D007455:Iodine / Q000172:deficiency; D010472:Perchlorates / Q000009:adverse effects* / Q000652:urine; D011247:Pregnancy / Q000187:drug effects* / Q000502:physiology*; D011261:Pregnancy Trimester, First; D013861:Thiocyanates / Q000009:adverse effects* / Q000652:urine; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects* / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D007454:Iodides; D010472:Perchlorates; D013861:Thiocyanates; D014284:Triiodothyronine; D013972:Thyrotropin; D007455:Iodine; C031760:thiocyanate; D013974:Thyroxine; C494474:perchlorate