Temporary ovarian failure in thyroid cancer patients after thyroid remnant ablation with radioactive iodine.

We studied ovarian function retrospectively in 66 women who had regular menstrual cycles before undergoing complete thyroidectomy for differentiated thyroid cancer and subsequent thyroid remnant ablation with 131I. Eighteen women developed temporary amenorrhea accompanied by increased serum gonadotropin concentrations during the first year after 131I therapy. No correlation was found between the radioactive iodine dose absorbed, thyroid uptake before treatment, oral contraceptive use, or thyroid autoimmunity. Only age was a determining factor, with the older women being the most affected. We conclude that radioiodine ablation therapy is followed by transient ovarian failure, especially in older women.