title: High prevalence of thyroid dysfunction in pregnant women.
abstract: OBJECTIVE
  Maternal thyroid dysfunction during pregnancy has been associated with adverse obstetric and neonatal outcomes. This prospective study evaluates the prevalence of these disorders in pregnant women.
  
  
  METHODS
  Serum levels of TSH, free T4 (fT4), and thyroperoxidase antibodies (TPO-Ab) were measured in 951 women at different gestational ages of pregnancy. Trimester-specific reference ranges for TSH were used to classify pregnant women into five groups: 1) Overt hypothyroidism (OH); 2) Subclinical hypothyroidism (SCH); 3) Isolated hypothyroxinemia (IH); 4) Low TSH (isolated or associated with high fT4); and 5) Normal. A classification was made also according to the lower and upper ranges provided by the manufacturer for thyroid hormones. Pregnant women who were at a high risk of developing thyroid disease were identified.
  
  
  RESULTS
  Altogether, 117 women (12.3%) had hypothyroidism and 25 (2.6%) had low TSH. The prevalence of both OH and SCH was higher in the high-risk group than in the low-risk group, but 17.9% of women with hypothyroidism were classified at low-risk. A family history of thyroid disorders and TPO-Ab positivity increased the risk of SCH. Using non-pregnant reference range for TSH, 10.6% of women were misclassificated.
  
  
  CONCLUSIONS
  The high prevalence of hypothyroidism observed in this study suggests that accurate thyroid screening with trimester specific reference ranges should be warranted, particularly in areas with mild to moderate iodine deficiencies.
authors.affiliation: Section of Endocrinology, Andrology and Internal Medicine, Department of Medical and Paediatric Sciences, University of Catania, Via S. Sofia 78, Catania, Italy. maria.altomare@tiscali.it
authors.forename: M
authors.initials: M
authors.lastname: Altomare
authors.forename: S
authors.initials: S
authors.lastname: La Vignera
authors.forename: P
authors.initials: P
authors.lastname: Asero
authors.forename: D
authors.initials: D
authors.lastname: Recupero
authors.forename: R A
authors.initials: RA
authors.lastname: Condorelli
authors.forename: P
authors.initials: P
authors.lastname: Scollo
authors.forename: A
authors.initials: A
authors.lastname: Gulisano
authors.forename: E
authors.initials: E
authors.lastname: Magro
authors.forename: D
authors.initials: D
authors.lastname: Tumino
authors.forename: S
authors.initials: S
authors.lastname: Tumino
authors.forename: E
authors.initials: E
authors.lastname: Vicari
authors.forename: V
authors.initials: V
authors.lastname: Leanza
authors.forename: R
authors.initials: R
authors.lastname: D'Agata
authors.forename: A E
authors.initials: AE
authors.lastname: Calogero
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000097:blood; D005260:Female; D005865:Gestational Age; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology*; D015995:Prevalence; D013959:Thyroid Diseases / Q000097:blood / Q000453:epidemiology*; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000097:blood; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D013963:Thyroid Hormones; C056626:thyroid microsomal antibodies; D013972:Thyrotropin; D007453:Iodide Peroxidase