title: [Longitudinal study of pituitary-thyroid axis in pregnancy].
abstract: The thyroid undergoes important changes during pregnancy. In order to evaluate changes of the hypophyseal-thyroid axis during this period we studied the thyroid function in 587 pregnants by determining serum TSH, free T4, TPO antibodies and betahCG in the 1st trimester and serum TSH, free T4 and TPOAb in to 2nd and 3rd. We observed a progressive rise in average serum TSH in the 2nd (2.14 mU/L) and 3rd (2.96 mU/L) trimesters when compared to the 1st (1.39 mU/L). Serum TSH values in the 1st trimester were inversely correlated with betahCG levels in as much as TSH levels below 0.4 mU/L corresponded to average betahCG levels of 129,000 UI/L whereas these were 34,200 UI/L in the normal TSH group. A slight decrease in free T4 levels was also observed in the 2nd and 3rd trimesters (averages 1st: 1.15; 2nd: 0.99; 3rd: 0.94 ng/dl). Thyroid autoimmunity defined as positive TPOAb occurred in 13.9% of our patients during pregnancy. No significant differences in TSH and free T4 medium values were found between patients with positive TPOAb and those without. However, a significantly higher proportion of pregnants had abnormal hormonal values throughout the trimesters. We conclude that thyroid function is affected by pregnancy with a tendency for decline as it progresses, a feature more easily observed in positive TPOAb group.
authors.affiliation: Serviços de Endocrinologia, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ. sleirorj@bol.com.br
authors.forename: Lino Sieiro
authors.initials: LS
authors.lastname: Netto
authors.forename: Cláudia Medina
authors.initials: CM
authors.lastname: Coeli
authors.forename: Eduardo
authors.initials: E
authors.lastname: Micmacher
authors.forename: Sheila da Costa
authors.initials: Sda C
authors.lastname: Mamede
authors.forename: Luiz Otávio
authors.initials: LO
authors.lastname: Nazar
authors.forename: Eunice Kássia
authors.initials: EK
authors.lastname: Correa
authors.forename: Mirella
authors.initials: M
authors.lastname: Arrastia
authors.forename: Daudt
authors.initials: D
authors.lastname: Galvão
authors.forename: Alexandru
authors.initials: A
authors.lastname: Buescu
authors.forename: Mário
authors.initials: M
authors.lastname: Vaisman
mesh_terms: D001323:Autoantibodies / Q000097:blood; D001324:Autoantigens / Q000097:blood; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000097:blood; D033862:Iron-Binding Proteins / Q000097:blood; D008137:Longitudinal Studies; D010902:Pituitary Gland / Q000502:physiology*; D011247:Pregnancy; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D033862:Iron-Binding Proteins; D013972:Thyrotropin; C056658:TPO protein, human; D007453:Iodide Peroxidase; D013974:Thyroxine