Effect of thyroid hormone replacement therapy on ovarian volume and androgen hormones in patients with untreated primary hypothyroidism

BACKGROUND AND OBJECTIVES: Primary hypothyroidism may be associated with ovarian enlargement and/ or cyst formation. We evaluated the effect of thyroid hormone replacement therapy on hormonal changes, ovarian volume and sonographic appearance. DESIGN AND SETTING: Open, prospective study of women admitted to university gynecology clinic. PATIENTS AND METHODS: The study included 26 patients with untreated hypothyroidism who had polycystic (n=10) or normal-appearing (n=16) ovaries and 20 euthyroidic controls. Basal serum total testosterone, free testosterone, androstenedione, dehydroepiandosterone-sulfate, prolactin, estradiol, luteinizing hormone, follicle-stimulating hormone, free T3, free T4 and thyroid-stimulating horone, together with ovarian volumes, were determined and repeated after euthyroidism was achieved. RESULTS: Ovarian volumes of patients with hypothyroidism were significantly greater compared with controls, and their magnitudes diminished significantly during thyroid hormone replacement therapy. Hypothyroidic patients with polycystic ovaries had significantly higher serum free testosterone and dehydroepiandosterone-sulfate, but lower androstenodione levels compared with those who had normal-appearing ovaries. Serum total testosterone concentrations were significantly higher in hypothyroidic patients without polycystic ovaries, and thyroid hormone replacement therapy achieved a significant reduction in total as well as free testosterone. CONCLUSION: Severe longstanding hypothyroidism leads to increased ovarian volume and/or cyst formation. A decrease in ovarian volume, resolution of ovarian cysts and reversal of the polycystic ovary syndrome-like appearance, together with improvement in serum hormone levels, occurred after euthyroidism was achieved.