Incidence of the postpartum diagnosis of thyroid eye disease in relation to thyroid function in Graves' disease

Abstract

It has been reported that Graves' disease (GD) sometimes improves spontaneously during pregnancy, although exacerbation of GD during postpartum period or relapse of hyperthyroidism caused by GD might occur. This study aimed to investigate the incidence of postpartum diagnosis of thyroid eye disease (TED) in relation to thyroid dysfunction. This retrospective cross-sectional study enrolled 11,104 deliveries from the patients with GD between January 2004 and August 2022. Within the 12-month postpartum period, 72 patients (0.65%) were diagnosed with TED. The thyroid function of the 72 patients comprised 9 remission, 13 continued antithyroid medicine, and 50 thyroid dysfunction; 30 newly diagnosed GD, 1 hypothyroidism, and 19 relapse/recurrence of GD. In the 49 patients with thyroid dysfunction, no difference was observed in the median values of thyroid-stimulating hormone (TSH) receptor antibody (TRAb) and TSH receptor stimulating antibody between the TED diagnosis and the development of hyperthyroidism. However, when the patients were classified into the newly developed GD and relapse/recurrence of GD groups, the difference became significant and the TRAb level was high in the newly developed GD (16.1 vs. 5.0 IU/L, p < 0.0001, and 15.0 vs. 6.0 IU/L, p = 0.0003). Thyroid dysfunction preceded TED diagnosis in more than half of the patients and the median time for each event was 6.5 vs. 8.1 months. The active phase TED was observed in 8 of the 72 patients. Of the 72 patients newly diagnosed with TED in postpartum, two-thirds were accompanied by thyroid dysfunction and 8 of them were in active phase.

Keywords: Graves’ disease; Postpartum; Thyroid eye disease; Thyroid orbitopathy.

Fig. 1. Patient flowchart

This figure shows the number of potential participants, the inclusion and exclusion criteria, and the final analytical sample. In this study, 11,104 deliveries of 8,092 patients were the analytical sample, and 72 patients had thyroid eye disease (TED). GD, Graves’ disease

Fig. 2. Characteristics of the patients divided by thyroid and eye condition

This figure shows the flowchart of the total participants divided by thyroid condition and eye condition. Herein, 10,762 pregnancies went through with the condition of GD and 342 patients developed GD after the deliveries. In total, 42 of 10,762 deliveries and 30 of 342 newly developed GD diagnosed TED in postpartum. The characteristics of the 72 patients diagnosed with TED were noted.

Fig. 3. Thyroid condition of the 72 patients at 12 months postpartum and TED assessment

This figure shows the thyroid condition of the 72 patients at 12 months postpartum on the left side and as the assessment of TED on the right side. In total, 9 remained in an euthyroid state, 13 continued medication, and 50 developed thyroid dysfunction. Of the 50 patients with thyroid dysfunction, 30 had newly developed GD, 16 experienced GD recurrence, 3 relapsed GD, and 1 developed hypothyroidism. At the assessment of TED, the patients were categorized based on their background condition and the treatment they required. In addition, they were categorized based on TED activity.

Graphical Abstract

Supplementary Fig. 1. Flowchart for TED management

This flowchart shows the recommendations for TED management in Japan. Regardless of the severity of TED, MRI is recommended for all patients with TED for evaluating activity.