EFFECT OF ESTROGEN-PROGESTIN HORMONAL REPLACEMENT THERAPY ON PLASMA ANTITHROMBIN-III OF POSTMENOPAUSAL WOMEN

Background. This study was performed to evaluate antithrombin III leve ls in postmenopausal women receiving hormonal replacement treatment. M ethods. It is a prospective randomized study concerning 19 postmenopau sal patients, aged 40 to 65 years, who received either continuous dail y oral equine conjugated estrogen 0.625 mg (group A, N=10) or daily tr ansdermal 17 beta-estradiol 50 mu g (group B, N=9). Medroxyprogesteron e acetate (5 mg/day, 14 days monthly) was given to all patients. Blood samples were obtained before and after 3, 6, 9 and 12 months of treat ment. Coagulation tests included Antithrombin III (functional method), prothrombin time, partial activated prothrombin time, thrombin time, factor V, fibrinogen, platelet count and euglobulin lysis time. Friedm an analysis of variance and Mann-Whitney test were used for statistica l analysis. Results. Antithrombin III level was reduced (p<0.05) in gr oup A but not in group B, although it remained within normal range. No changes were detected in the other coagulation tests. Conclusions. Th ese data suggest that oral conjugated estrogen replacement reduces fun ctional ATIII, whereas transdermal estradiol replacement therapy does not modify it.