title: Treatment with fixed thyroxine doses in pregnant women with subclinical hypothyroidism.
abstract: BACKGROUND
  Hypothyroidism is usually treated with thyroxine doses on patient weight. In some cases, however, fixed doses have proved to useful to normalize TSH levels, which is especially important during pregnancy.
  
  
  METHODS
  Sixty-eight women diagnosed with subclinical hypothyroidism, autoimmune or not, during pregnancy were given a fixed dose of thyroxine 50 mcg/day. TSH measurements were performed to assess the need to change the dose, which was increased or decreased by 25 mcg/day when necessary.
  
  
  RESULTS
  With a dose of 50 mcg/day of thyroxine, 42% of patients reached a TSH level less than 3 μU/mL, 79.4% reached a TSH level less than 4.5 μU/mL, and 20.6% had TSH levels higher than 4.5 μU/mL.
  
  
  CONCLUSIONS
  Our data suggest that a fixed dose of thyroxine 50 mcg/day is inadequate in a significant proportion of pregnancy-diagnosed hypothyroidism regardless of whether the reference of TSH level used is 4.5 or 3 μU/mL. S starting dose of 75 mcg/day is probably more adequate, but studies are needed to evaluate the possibility of overtreatment with such dose.
authors.affiliation: Servicio de Endocrinología y Nutrición, Complexo Hospitalario Universitario de Vigo, Vigo, Pontevedra, España. ineseoane@yahoo.es
authors.forename: Inés
authors.initials: I
authors.lastname: Seoane Cruz
authors.forename: Manuel
authors.initials: M
authors.lastname: Penín Álvarez
authors.forename: Reyes
authors.initials: R
authors.lastname: Luna Cano
authors.forename: Ricardo Víctor
authors.initials: RV
authors.lastname: García-Mayor
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000188:drug therapy*; D007455:Iodine / Q000008:administration & dosage / Q000627:therapeutic use; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000188:drug therapy*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin; C056626:thyroid microsomal antibodies; D013972:Thyrotropin; D007455:Iodine; D013974:Thyroxine