Amenorrhea with low normal thyroid function and thyroxine treatment

The effect of thyroxine treatment in cases of functional amenorrhea accompanied by low normally thyroid function was studied. During six months of follow-up, regular or single menstrual cycles were restored in ten of the 17 patients with thyroxine treatment and in four of the 11 patients without thyroxine treatment. During thyroxine treatment, thyroxine and free thyroxine index levels were elevated and serum testosterone levels decreased, but no significant changes were observed in serum estradiol, prolactin, follicle-stimulating hormone or luteinizing hormone levels. In the thyroid-releasing hormone/luteinizing-releasing hormone test, the thyroid-stimulating hormone response was markedly suppressed, but there were no changes in follicle-stimulating hormone, luteinizing hormone or prolactin responses. In one patient with primary hypothyroidism, regular menstrual cycles were restored and serum prolactin and thyroid-stimulating hormone levels normalized during thyroxine treatment. Thyroxine treatment seems to have benefits in some amenorrheic patients with low normal thyroid function.