THYROID PROFILE MODIFICATIONS DURING ORAL HORMONE REPLACEMENT THERAPYIN POSTMENOPAUSAL WOMEN

There are few data available about changes in thyroid hormone profiles after hormone replacement therapy (HRT). We analyzed the effect of tw o different oral estrogens/progestins (E/P) associations on thyroid ho rmones and thyroxine-binding globulin (TBG) level in 14 postmenopausal normal women distributed at random into two groups. Both groups recei ved daily for a year 2 mg of estradiol valerianate per os. In Group A (n = 7), estrogen war associated with norethisterone acetate. In Group B, estrogen was associated with promegestone in a similar schedule to Group A. Blood samples were withdrawn to measure estradiol (E2), thyr oxine (T4), triiodothyronine (T3), free T4 (fT4), thyroid-stimulating hormone (TSH) and TBG before and after 3, 6 and 12 months of treatment . Estradiol level increased significantly in both groups, being higher in Group A than in B. Under therapy, T4 and TBG level were increased in both groups, but within the normal range. T4 mean level increased b y 34% in Group A and 20% in Group B. TBG increment was slightly signif icant for Group A (p < 0.02); With only a trend in Group B (p = 0.08). T3, fT4 and TSH level did not change significantly and remained withi n the normal range. Oral therapy with associated E/P producer moderate increases in T4 and TBG level. Our results suggest that in postmenopa usal women on oral HRT,fT4 and TSH level are the most useful tool to e valuate the thyroid axis status.