Thyroid Research Thyroid Research Archive Hyperthyroidism

Polycystic ovaries in women with hyperthyroidism

(March 2003)

The background of the study. Some women with hyperthyroidism have irregular menstrual cycles, and they may not ovulate regularly. In this study, menstrual cycle characteristics, ovarian structure, and serum androgens were determined in women with hyperthyroidism.

How the study was done. The study subjects were 18 women with newly diagnosed hyperthyroidism, most of whom had Graves' disease. The women were studied by ovarian ultrasonography and measurements of serum total and free testosterone and sex hormone-binding globulin (SHBG) before and after treatment with methimazole for one and three months. The results of ultrasonography were analyzed according to the phase of the woman's menstrual cycle and were compared with the results at the same phase in normal women.

The results of the study. All 18 women with hyperthyroidism had had regular menstrual cycles in the past. Before treatment, 8 women had regular cycles and 10 had irregular cycles, 7 of whom had normal cycles during treatment. Fifteen women had abnormal findings on ovarian ultrasonography; the abnormalities included the presence of multiple or single large ovarian follicles at inappropriate times of the cycle and ovarian cysts. The results of ultrasonography were abnormal in 9 of the 11 women who were studied after treatment for one month, but were normal in all 7 women studied after treatment for three months. As compared with the normal women, the women with hyperthyroidism had higher serum total testosterone and SHBG concentrations, but their serum free (not bound to protein) testosterone concentrations were normal.

The conclusions of the study. Some women with hyperthyroidism have polycystic ovaries, as determined by ultrasonography, and the changes resolve during antithyroid drug therapy. They do not, however, have the hormonal abnormalities characteristic of the polycystic ovarian syndrome.

The original article. Skjoldebrand Sparre L, Kollind M, Carlstrom K. Ovarian ultrasound and ovarian and adrenal hormones before and after treatment for hyperthyroidism. Gynecol Obstet Invest 2002;54:50-5.