Effects of Radioactive Iodine Therapy on Ovarian Reserve: A Prospective Pilot Study

Thyroid carcinoma is the most common endocrine malignancy. Surgery is the standard therapeutic approach for patients with differentiated thyroid carcinoma (DTC), followed by radioiodine (RAI) therapy if indicated. For women with DTC, the effects of RAI therapy on gonadal and reproductive function are an important consideration. This study aimed to evaluate the effects of RAI therapy on ovarian function. A total of 33 premenopausal women were enrolled in this study. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, and anti-Müllerian hormone (AMH) levels during the early follicular phase were measured before and 3, 6, and 12 months after RAI therapy. The Friedman and Wilcoxon tests were used to detect changes in FSH, AMH, LH, and estradiol levels induced by RAI therapy over time. The patients' ages ranged from 21 to 38 years, with a mean age of 31.15 ± 4.83 years. The median follow-up was 19 months (range 4-26 months). The median AMH levels were 3.25 ng/mL (range 0.32-17.42 ng/mL), 1 ng/mL (range 0.01-3.93 ng/mL), 1.13 ng/mL (range 0.08-6.12 ng/mL), and 1.37 ng/mL (range 0.09-6.1 ng/mL) before and at 3, 6, and 12 months after RAI therapy, respectively. The median FSH levels were 6.6 mIU/mL (range 3.78-15.5 mIU/mL), 5.83 mIU/mL (range 4.19-35.36 mIU/mL), 7.71 mIU/mL (range 4.24-16.25 mIU/mL), and 7.04 mIU/mL (range 4.93-19.96 mIU/mL) before and at 3, 6, and 12 months after RAI therapy, respectively. The AMH levels were higher before than after RAI therapy (p = 0.001). The AMH levels did not differ significantly between the three time points (p > 0.05). The FSH, LH, and estradiol levels were similar before and after RAI therapy (p > 0.05). AMH is considered an important marker of ovarian reserve. Ovarian reserve decreased after RAI therapy. More attention may be needed when considering RAI therapy for patients with reduced ovarian reserve.