title: Is age a risk factor for hypothyroidism in pregnancy? An analysis of 5223 pregnant women.
abstract: BACKGROUND
  The guidelines of American Thyroid Association from 2011 include age over 30 as one of the risk factors for hypothyroidism in pregnancy.
  
  
  OBJECTIVE
  Our objective was to verify whether age increases the risk of autoimmune thyroid disease in pregnancy.
  
  
  METHODS
  We performed a cross-sectional study in 2006-2008 with laboratory assessment in a single center using primary care gynecological ambulances in cooperation with a referral center.
  
  
  METHODS
  The study included 5223 consecutive pregnant women in gestational wk 9-12.
  
  
  METHODS
  We assessed the occurrence of pathological serum concentrations of TSH and/or antibodies against thyroperoxidase (TPOAb) with regard to age. Reference interval for TSH was 0.06-3.67 mU/liter; the upper cutoff value for TPOAb was 143 kU/liter.
  
  
  RESULTS
  Overall, 857 women (16.4%) were positively screened. Of these, 294 (5.63%) had TSH elevation, 146 (2.79%) had TSH suppression, 561 (10.74%) were TPOAb positive, and 417 (7.98%) were euthyroid and TPOAb positive. The average age of women was 31.1 yr. The prevalence of hypothyroidism was 5.5 and 5.8% in women aged 30 or older and those under 30 yr, respectively (P value nonsignificant). Using a logistic regression model, we didn't find any significant association between age and serum TSH suppression, TSH elevation, or TPOAb positivity (P = 0.553, P = 0.680, and P = 0.056, respectively) or between age and TSH elevation with TPOAb positivity (P = 0.967). In a subgroup analysis of risk factors for hypothyroidism in 132 hypothyroid women, addition of age 30 or older increased the proportion of women identified in a case-finding screening strategy from 55.3 to 85.6%.
  
  
  CONCLUSIONS
  Prevalence of autoimmune thyroid disease does not increase with age in pregnant women; however, addition of age 30 or over to the case-finding screening strategy may substantially improve its efficiency due to a larger number of women screened.
authors.affiliation: Third Department of Medicine, General University Hospital and First Faculty of Medicine, Charles University in Prague, U nemocnice 1, Prague 2, 128 08, Czech Republic. eliska.potlukova@seznam.cz
authors.forename: Eliska
authors.initials: E
authors.lastname: Potlukova
authors.forename: Oto
authors.initials: O
authors.lastname: Potluka
authors.forename: Jan
authors.initials: J
authors.lastname: Jiskra
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Limanova
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Telicka
authors.forename: Jana
authors.initials: J
authors.lastname: Bartakova
authors.forename: Drahomira
authors.initials: D
authors.lastname: Springer
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001323:Autoantibodies / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology* / Q000276:immunology; D007453:Iodide Peroxidase / Q000276:immunology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000276:immunology; D011261:Pregnancy Trimester, First / Q000276:immunology; D015995:Prevalence; D012307:Risk Factors; D013967:Thyroiditis, Autoimmune / Q000453:epidemiology* / Q000276:immunology; D013972:Thyrotropin / Q000097:blood; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D013972:Thyrotropin; D007453:Iodide Peroxidase