Thyroid function parameters and TSH-receptor antibodies in healthy subjects and Graves' disease patients: a sequential study before, during and after pregnancy.

The changes in thyroid function and in TSH receptor antibody titers were analyzed in a prospective sequential study before, during and after pregnancy in a group of 15 healthy women and 45 patients with Graves' disease. Twenty-five patients with Graves' disease were untreated before pregnancy (Group A) and twenty treated with carbimazole throughout pregnancy (Group B). In healthy pregnant women serum FT4 levels were slightly but significantly elevated early in pregnancy (p < 0.05) and lower during the third trimester (p < 0.01), compared to pregestational values (although within the reference range of nonpregnant subjects). During postpartum, serum FT4 reverted to values similar to those found before pregnancy. Serum TSH levels showed a slight increment during gestation with a significant decrease (p < 0.01) in the early postpartum period. There was a significant increase in serum thyroglobulin (Tg) during the first trimester (p < 0.01); Tg levels remaining markedly elevated throughout gestation. After delivery, Tg progressively decreased, but were still above normal, six months later in 27% of subjects. TSH-receptor antibody titers were normal but tended to decrease during late gestation; a significant rebound was observed in late postpartum, even though most individual values remained in the normal range. When we compared "active" and "remission" Graves' disease patients, the concentration of FT4 was significantly higher in group B ("active") than in group A ("remission" (p < 0.01) during early gestation. Serum Tg was also significantly higher in Group B than in Group A before pregnancy (p < 0.01), and during late gestation and postpartum (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)