The Postpartum Recurrence of Graves'Disease and its Contributing Factors / 대한내분비학회지

ABSTRACT

BACKGROUND: Pregnancy affects the course of Graves' Disease (GD), and patients who initially maintain euthyroid function into their middle trimester with minimum doses of antithyroid drugs become exacerbated after delivery. Even patients who are completely cured, requiring no treatment during pregnancy, can relapse after delivery. In this study, we examined the postpartum changes in the thyroid functions of patients with GD, and attempted to determine the factors contributing to these changes. METHODS: The study subjects were recruited from pregnant women visiting our outpatient clinic for routine prenatal evaluations. 45 women previously diagnosed with GD, who had been treated and cured with hyperthyroidism, and were no longer taking any thyroid medications, were evaluated for 1 year post delivery. RESULTS: Among 45 patients, 20 (44.4%) developed thyroid disorders following delivery. Postpartum thyroiditis (PPT) developed in 8 patients (17.8%), and GD developed in 12 (26.0%). The onset of the PPT disease 3.1 +/- 1.4 months following delivery, which was significantly earlier than the 6.7 +/- 2.7 months required for the post delivery onset of GD (p=0.003). The TBII values, measured during the thyrotoxic state in each womaen, were negative in women with PPT and positive in 71.4% of women with GD (p=0.030). The duration of treatment for hyperthyroidism prior or pregnancy, the number of recurrences, and the time interval without treatment, were not associated with the development of postpartum thyroid disorders. Whereas, the mean number of past pregnancies for women who developed PPT was 3.9 +/- 2.1, and was significantly higher than the 2.2+/- 1.7 for women developing no thyroid dysfunctions (p=0.044). In 13 women their initial onset of GD occurred within one year postpartum, 7 (53.8%) having had a recurrence, which was significantly higher than in women whose disease onset occurred unrelated to delivery (5 of 32 women 15.6%). CONCLUSION: Women with GD developed postpartum thyroid dysfunctions in 44.4% of cases. Women whose initial disease onset occurred within one year postpartum had higher recurrences of GD, and women who developed PPT had a history of higher gravidity compared to the euthyroid women postpartum. Therefore, if women with GD develop postpartum thyroid dysfunctions, the diagnosis should be made, and a treatment modality planned, following careful considerations of the patients' past obstetric history, changes in clinical manifestations and the TBII values.