title: Maternal perchlorate levels in women with borderline thyroid function during pregnancy and the cognitive development of their offspring: data from the Controlled Antenatal Thyroid Study.
abstract: OBJECTIVE
  Thyroid dysfunction is associated with impaired cognitive development. Perchlorate decreases thyroidal iodine uptake, potentially reducing thyroid hormone production. It is unclear whether perchlorate exposure in early life affects neurodevelopment.
  
  
  METHODS
  Historical cohort analysis.
  
  
  METHODS
  From 2002 to 2006, 21,846 women at gestational age <16 weeks recruited from antenatal clinics in Cardiff, UK and Turin, Italy were enrolled in the Controlled Antenatal Thyroid Screening Study (CATS). We undertook a retrospective analysis of 487 mother-child pairs in mothers who were hypothyroid/hypothyroxinemic during pregnancy and analyzed whether first trimester maternal perchlorate levels in the highest 10% of the study population were associated with increased odds of offspring IQ being in the lowest 10% at 3 years of age.
  
  
  METHODS
  Maternal urinary perchlorate, offspring IQ.
  
  
  RESULTS
  Urine perchlorate was detectable in all women (median 2.58 μg/L); iodine levels were low (median 72 μg/L). Maternal perchlorate levels in the highest 10% of the population increased the odds of offspring IQ being in the lowest 10% OR = 3.14 (95% CI 1.38, 7.13) P = .006 with a greater negative impact observed on verbal OR = 3.14 (95% CI 1.42, 6.90) P = .005 than performance IQ. Maternal levothyroxine therapy did not reduce the negative impact of perchlorate on offspring IQ.
  
  
  CONCLUSIONS
  This is the first study using individual-level patient data to study maternal perchlorate exposure and offspring neurodevelopment and suggests that high-end maternal perchlorate levels in hypothyroid/hypothyroxinemic pregnant women have an adverse effect on offspring cognitive development, not affected by maternal levothyroxine therapy. These results require replication in additional studies, including in the euthyroid population.
authors: Thyroid Research Group (P.N.T., O.E.O., C.H., C.M.D., J.H.L.), Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff, United Kingdom CF14 4XN; Department of Paediatric Psychology (R.M., R.P., S.C.), St. David's Children's Centre, Cardiff, United Kingdom CF11 9XB; Città della Salute e della Scienza - Ospedale Sant'Anna (E.C., A.M.,), Turin, Italy 10100; Wolfson Institute of Preventive Medicine (M.J., J.P.B.), Barts and the London School of Medicine and Dentistry, London, United Kingdom B15 2TT; University College Dublin School of Medicine (P.S.), University College, Dublin, Ireland, Dublin 4; and Section of Endocrinology, Diabetes, and Nutrition (L.E.B., E.N.P.), Boston University School of Medicine, Boston, Massachusetts.
authors: Peter N
authors: PN
authors: Taylor
authors: Onyebuchi E
authors: OE
authors: Okosieme
authors: Rhian
authors: R
authors: Murphy
authors: Charlotte
authors: C
authors: Hales
authors: Elisabetta
authors: E
authors: Chiusano
authors: Aldo
authors: A
authors: Maina
authors: Mohamed
authors: M
authors: Joomun
authors: Jonathan P
authors: JP
authors: Bestwick
authors: Peter
authors: P
authors: Smyth
authors: Ruth
authors: R
authors: Paradice
authors: Sue
authors: S
authors: Channon
authors: Lewis E
authors: LE
authors: Braverman
authors: Colin M
authors: CM
authors: Dayan
authors: John H
authors: JH
authors: Lazarus
authors: Elizabeth N
authors: EN
authors: Pearce
mesh_terms: D002675:Child, Preschool; D003071:Cognition; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000503:physiopathology / Q000523:psychology / Q000652:urine*; D007360:Intelligence; D018811:Maternal Exposure; D009483:Neuropsychological Tests; D010472:Perchlorates / Q000652:urine*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000503:physiopathology / Q000523:psychology / Q000652:urine*; D011297:Prenatal Exposure Delayed Effects / Q000139:chemically induced / Q000523:psychology*; D012189:Retrospective Studies; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000503:physiopathology*
chemical_list: D010472:Perchlorates