title: Maternal and Child's Thyroid Function and Child's Intellect and Scholastic Performance.
abstract: BACKGROUND
  Maternal hypothyroidism and/or hypothyroxinemia have been associated with child's poor neuropsychological development, but the results have been inconsistent.
  
  
  METHODS
  The Northern Finland Birth Cohort 1986 included all expected births within a year (9362 women, 9479 children) from the two northernmost provinces of Finland. Maternal serum samples (n = 5791) were obtained in early pregnancy (M ± SD = 10.7 ± 2.8 weeks' gestation), and serum samples from their children were obtained at 16 years of age (n = 5829). All samples were analyzed for thyrotropin, free thyroxine (fT4), and thyroid peroxidase antibodies. The children's school performance was evaluated by their main teachers at eight years of age, as well as by the adolescents themselves at 16 years of age. Data on possible severe intellectual deficiency and mild cognitive limitation were collected from healthcare records and registries for all children. Logistic regression estimated the odds of poor school performance or severe intellectual deficiency/mild cognitive limitation associated with exposure to maternal thyroid dysfunction. The odds of poor school performance associated with the adolescents' own thyroid function at age 16 were also estimated. Results are presented as odds ratios (OR) with confidence intervals (CI), adjusted for maternal/family covariates and child's sex.
  
  
  RESULTS
  Girls of mothers with subclinical hypothyroidism had more self-evaluated difficulties in mathematics than did girls of euthyroid mothers (OR 1.62 [CI 1.06-2.49]). Boys of hypothyroxinemic mothers repeated a school class more often than did boys of euthyroid mothers (OR 5.46 [CI 1.19-25.06]). Adolescents of hyperthyroid mothers had increased odds of poor self-evaluated performance in mathematics (OR 1.61 [CI 1.01-2.49]). Maternal thyroid dysfunction did not increase the odds of a child having severe intellectual deficiency/mild cognitive limitation. At 16 years of age, girls with hyperthyroidism by laboratory measurements had more difficulties in Finnish language (OR 2.82 [CI 1.42-5.61]) than did euthyroid girls. Boys with hypothyroxinemia by laboratory measurement had higher odds of having difficulties in Finnish and/or mathematics (OR 2.13 [CI 1.26-3.62]) than did euthyroid boys.
  
  
  CONCLUSIONS
  Maternal thyroid dysfunction during early pregnancy was associated with poorer scholastic performance of the adolescent. Additionally, adolescents' own thyroid dysfunction was associated with difficulties in school performance assessed by self-evaluation.
authors.affiliation: 1 Department of Obstetrics and Gynecology, University of Oulu , Oulu, Finland .|2 Clinic of Obstetrics and Gynecology, Oulu University Hospital , Oulu, Finland .|3 Institute of Health Sciences, University of Oulu , Oulu, Finland .|4 Department of Children, Young People, and Families, National Institute for Health and Welfare , Oulu, Finland .
authors.forename: Fanni
authors.initials: F
authors.lastname: Päkkilä
authors.affiliation: 5 Department of Chronic Disease Prevention, National Institute for Health and Welfare , Oulu, Finland .|6 Northern Finland Laboratory Centre Nordlab, Oulu University Hospital , Oulu, Finland .|7 Department of Clinical Chemistry, University of Oulu , Oulu, Finland .|8 Medical Research Center Oulu, Oulu University Hospital , Oulu, Finland .
authors.forename: Tuija
authors.initials: T
authors.lastname: Männistö
authors.affiliation: 1 Department of Obstetrics and Gynecology, University of Oulu , Oulu, Finland .|2 Clinic of Obstetrics and Gynecology, Oulu University Hospital , Oulu, Finland .|8 Medical Research Center Oulu, Oulu University Hospital , Oulu, Finland .
authors.forename: Anna-Liisa
authors.initials: AL
authors.lastname: Hartikainen
authors.affiliation: 6 Northern Finland Laboratory Centre Nordlab, Oulu University Hospital , Oulu, Finland .
authors.forename: Aimo
authors.initials: A
authors.lastname: Ruokonen
authors.affiliation: 4 Department of Children, Young People, and Families, National Institute for Health and Welfare , Oulu, Finland .
authors.forename: Heljä-Marja
authors.initials: HM
authors.lastname: Surcel
authors.affiliation: 4 Department of Children, Young People, and Families, National Institute for Health and Welfare , Oulu, Finland .
authors.forename: Aini
authors.initials: A
authors.lastname: Bloigu
authors.affiliation: 1 Department of Obstetrics and Gynecology, University of Oulu , Oulu, Finland .|2 Clinic of Obstetrics and Gynecology, Oulu University Hospital , Oulu, Finland .|8 Medical Research Center Oulu, Oulu University Hospital , Oulu, Finland .
authors.forename: Marja
authors.initials: M
authors.lastname: Vääräsmäki
authors.affiliation: 3 Institute of Health Sciences, University of Oulu , Oulu, Finland .|4 Department of Children, Young People, and Families, National Institute for Health and Welfare , Oulu, Finland .|5 Department of Chronic Disease Prevention, National Institute for Health and Welfare , Oulu, Finland .|8 Medical Research Center Oulu, Oulu University Hospital , Oulu, Finland .|9 Department of Epidemiology and Biostatistics, MRC Health Protection Agency (HPA) Centre for Environment and Health, School of Public Health, Imperial College London , United Kingdom .
authors.forename: Marjo-Riitta
authors.initials: MR
authors.lastname: Järvelin
authors.affiliation: 10 PEDEGO Research Unit, Department of Child Psychiatry, University of Oulu , Oulu, Finland .|11 Department of Child Psychiatry, Oulu University Hospital , Oulu, Finland .
authors.forename: Irma
authors.initials: I
authors.lastname: Moilanen
authors.affiliation: 1 Department of Obstetrics and Gynecology, University of Oulu , Oulu, Finland .|2 Clinic of Obstetrics and Gynecology, Oulu University Hospital , Oulu, Finland .|8 Medical Research Center Oulu, Oulu University Hospital , Oulu, Finland .
authors.forename: Eila
authors.initials: E
authors.lastname: Suvanto
mesh_terms: D000124:Achievement; D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000097:blood; D002648:Child; D002657:Child Development; D015331:Cohort Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000453:epidemiology* / Q000523:psychology; D008607:Intellectual Disability / Q000453:epidemiology*; D007360:Intelligence; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology* / Q000523:psychology; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000523:psychology; D011446:Prospective Studies; D012737:Sex Factors; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D055815:Young Adult
chemical_list: D001323:Autoantibodies; C056626:thyroid microsomal antibodies; D013972:Thyrotropin; D013974:Thyroxine