ABSTRACT
OBJECTIVES: Recently, studies have shown an association between antiperoxidase for the detection of thyroid autoimmunity (TAI) and abortion. Another point to be considered is the association of high risk of abortion and maternal age. The aim of the present study was to evaluate if the association between TAI and miscarriage could also be verified whether a population of unselected pregnant young women who normally present a low risk of miscarriage. MATERIALS AND METHODS: We studied 534 pregnant women, by determining their serum thyroid antiperoxidase antibodies (TPO-Abs), thyrotropin (TSH) and free thyroxine (fT4) levels. Our end point was the pregnancy loss or live birth. RESULTS: Age ranged from 12 to 49 years (mean +/- S.D.; 23.5 +/- 5.9). Of 534 women, 29 (5.4%) were TPO-Ab positive. TSH levels were significantly higher in TPO-Ab-positive women compared with TPO-Ab negative women (median; 1.9 versus 1.1; P = 0.001). Elevated TSH levels were found in 13.8% (4 of 29) of the TPO-Ab-positive women compared with only 2.4% (12 of 505) in the TPO-Ab-negative women. There were no significant differences in fT4 levels in relation with autoimmunity and risk of miscarriage. The overall risk of miscarriage was 2.4% (13 of 534). Risk of miscarriage was significantly higher among women older than 35 years (7.7%), TPO-Ab positive (10.3%) and presenting high levels of TSH (12.5%). These factors remained independently associated with the risk of miscarriage in full multivariate analysis. CONCLUSIONS: We conclude that TAI is independently associated with is a higher risk of miscarriage in a population of unselected pregnant presenting a low risk of miscarriage.
Subject(s)
Abortion, Spontaneous/etiology , Autoantibodies/blood , Autoimmunity , Thyroid Gland/immunology , Thyrotropin/blood , Abortion, Spontaneous/blood , Abortion, Spontaneous/epidemiology , Adolescent , Adult , Age Factors , Autoimmune Diseases/complications , Autoimmune Diseases/diagnosis , Brazil/epidemiology , Child , Cohort Studies , Female , Humans , Maternal Age , Middle Aged , Peroxidase/immunology , Pregnancy , Risk Factors , Thyroid Diseases/blood , Thyroid Diseases/complications , Thyroid Diseases/immunology , Thyroid Gland/enzymology , Thyroxine/bloodABSTRACT
A tireóide sofre importantes modificações durante a gravidez. Visando mostrar as modificações no eixo hipófise-tireóide ao longo deste período, estudamos a função tireoidiana de 587 mulheres, com dosagens de TSH, T4 livre, anti-TPO, betahCG no 1°. trimestre e TSH, T4 livre e anti-TPO no 2°. e 3°. trimestres. Observamos aumento progressivo do TSH no 2°. (média: 2,14mU/L) e 3°. (média: 2,76mU/L) trimestres, em relação ao 1°. (média: 1,39mU/L). No grupo com TSH abaixo do valor de referência (0,4mU/L) no 1°. trimestre, a média de bhCG foi de 129.200UI/L, enquanto no grupo que apresentou níveis normais de TSH, a média foi de 34.200UI/L. Observamos, também, uma ligeira diminuição do T4 livre no 2°. e 3°. trimestres em relação ao 1°. (médias: 1°: 1,15; 2°: 0,99; 3°: 0,94ng/dl). A presença de anti-TPO positivo ocorreu em 13,9 por cento das mulheres. Não foram observadas alterações significativas nos valores médios de TSH e T4 livres naquelas com ou sem auto-imunidade. Entretanto, proporções significativamente maiores de gestantes apresentaram valores hormonais fora da faixa da normalidade em todos os trimestres da gestação. Concluímos que a função tireoidiana é afetada pela gravidez, com tendência ao declínio durante seu progresso, sendo este fenômeno mais marcante no grupo de gestantes anti-TPO positivas.
Subject(s)
Female , Humans , Pregnancy , Pituitary Gland/physiology , Thyroid Gland/physiology , Autoantibodies/blood , Autoantigens/blood , Cohort Studies , Iodide Peroxidase/blood , Iron-Binding Proteins/blood , Longitudinal Studies , Thyrotropin/blood , Thyroxine/bloodABSTRACT
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.
