RESUMO
OBJECTIVE: Thyroid function and gonadal axis are related throughout a woman's fertile period. Modifications of thyroid hormone levels have been reported as a consequence of controlled ovarian stimulation for infertility. METHODS: A 28-year-old woman with regular menses and previous evidence of euthyroidism underwent controlled ovarian hyperstimulation (COH) for assisted reproductive technology (ART). Free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), and autoantibodies against thyroperoxidase and thyroglobulin (TPOAb and TgAb, respectively) were measured before COH. FT4, FT3, and TSH were re-evaluated 6 days, 2 weeks (during oocyte retrieval), and 1 month after the beginning of the procedure. RESULTS: The baseline evaluation revealed subclinical autoimmune hypothyroidism. The patient was hypothyroidic at 6 days and 2 weeks and spontaneously returned to euthyroidism 1 month after COH. CONCLUSION: This is the first case of a woman with an unknown subclinical autoimmune hypothyroidism who developed overt and transient hypothyroidism as a consequence of COH. Careful thyroid evaluation is advised for women undergoing COH.
