title: Detection of thyroid dysfunction in early pregnancy: Universal screening or targeted high-risk case finding?
abstract: BACKGROUND
  Maternal subclinical hypothyroidism during pregnancy is associated with various adverse outcomes. Recent consensus guidelines do not advocate universal thyroid function screening during pregnancy but recommend testing high-risk pregnant women with a personal history of thyroid or other autoimmune disorders or with a family history of thyroid disorders.
  
  
  OBJECTIVE
  The objective of the study was to assess efficacy of the targeted high-risk case-finding approach in identifying women with thyroid dysfunction during early pregnancy.
  
  
  METHODS
  This was a single-center cohort study. PATIENTS/OUTCOME MEASURES: We prospectively analyzed TSH, free T4 and free T3 in 1560 consecutive pregnant women during their first antenatal visit (median gestation 9 wk). We tested thyroperoxidase antibodies in 1327 (85%). We classified 413 women (26.5%), who had a personal history of thyroid or other autoimmune disorders or a family history of thyroid disorders, as a high-risk group. We examined whether testing only such a high-risk group would pick up most pregnant women with thyroid dysfunction.
  
  
  RESULTS
  Forty women (2.6%) had raised TSH (>4.2 mIU/liter). The prevalence of raised TSH was higher in the high-risk group [6.8 vs. 1% in the low-risk group, relative risk (RR) 6.5, 95% confidence interval (CI) 3.3-12.6, P < 0.0001]. Presence of personal history of thyroid disease (RR 12.2, 95% CI 6.8-22, P < 0.0001) or other autoimmune disorders (RR 4.8, 95% CI 1.3-18.2, P = 0.016), thyroperoxidase antibodies (RR 8.4, 95% CI 4.6-15.3, P < 0.0001), and family history of thyroid disorders (RR 3.4, 95% CI 1.8-6.2, P < 0.0001) increased the risk of raised TSH. However, 12 of 40 women with raised TSH (30%) were in the low-risk group.
  
  
  CONCLUSIONS
  Targeted thyroid function testing of only the high-risk group would miss about one third of pregnant women with overt/subclinical hypothyroidism.
authors.affiliation: Department of Endocrinology, Royal Devon, Exeter Hospital, Exeter EX2 5DW, United Kingdom. bijay.vaidya@pms.ac.uk
authors.forename: Bijay
authors.initials: B
authors.lastname: Vaidya
authors.forename: Sony
authors.initials: S
authors.lastname: Anthony
authors.forename: Mary
authors.initials: M
authors.lastname: Bilous
authors.forename: Beverley
authors.initials: B
authors.lastname: Shields
authors.forename: John
authors.initials: J
authors.lastname: Drury
authors.forename: Stewart
authors.initials: S
authors.lastname: Hutchison
authors.forename: Rudy
authors.initials: R
authors.lastname: Bilous
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis*; D011261:Pregnancy Trimester, First; D012016:Reference Values; D012306:Risk; D013959:Thyroid Diseases / Q000175:diagnosis*; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use
chemical_list: D013972:Thyrotropin; D013974:Thyroxine