title: Targeted thyroid testing during pregnancy in clinical practice.
abstract: OBJECTIVE
  To evaluate the efficacy of a targeted thyroid testing approach during pregnancy in clinical practice.
  
  
  METHODS
  This is a retrospective cohort study performed within Uppsala County, Sweden. Data were derived from the population-based Uppsala Biobank of Pregnant Women, in which blood samples are collected in conjunction with the routine ultrasound screening in gestational week 17-19. For this study, 5,254 pregnant women with an estimated date of delivery between January 1, 2009, and December 31, 2011, were included. On review of their medical records, women who were tested for thyroid dysfunction during pregnancy in clinical practice were identified (n=891). From the remaining untested women, 1,006 women were randomly selected for analyses of thyrotropin (TSH), free thyroxine levels, and thyroid peroxidase antibodies. Thyroid-stimulating hormone levels in both groups were analyzed with regard to trimester-specific upper reference levels as recommended by the International Endocrine Society Guidelines.
  
  
  RESULTS
  The proportion of trimester-specific TSH elevation was 12.6% in the targeted thyroid testing group and 12.1% in the untested group (P=.8; odds ratio [OR] 1.04, 95% confidence interval [CI] 0.79-1.37). The proportion of overt hypothyroidism was 1.1% and 0.7% in the groups, respectively (P=.4; OR 1.57, 95% CI 0.55-4.45).
  
  
  CONCLUSIONS
  The prevalence of trimester-specific elevated TSH and overt hypothyroidism was equal in targeted thyroid tested and untested women. When implemented in clinical practice, targeted thyroid testing is unsatisfactory. If ongoing studies provide support for treatment of pregnant women with elevated TSH, universal thyroid testing appears the most reasonable approach.
  
  
  METHODS
  : II.
authors.affiliation: Departments of Women's and Children's Health and Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Michaela
authors.initials: M
authors.lastname: Granfors
authors.forename: Helena
authors.initials: H
authors.lastname: Åkerud
authors.forename: Johan
authors.initials: J
authors.lastname: Skogö
authors.forename: Mats
authors.initials: M
authors.lastname: Stridsberg
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Wikström
authors.forename: Inger
authors.initials: I
authors.lastname: Sundström-Poromaa
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D013548:Sweden; D013959:Thyroid Diseases / Q000175:diagnosis* / Q000503:physiopathology; D013960:Thyroid Function Tests / Q000379:methods*; D013961:Thyroid Gland / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D001323:Autoantibodies; D013972:Thyrotropin; D007453:Iodide Peroxidase; D013974:Thyroxine