Altered uterine artery blood flow impedance after danazol therapy: possible mode of action in dysfunctional uterine bleeding.

OBJECTIVE: To test the hypothesis that danazol increases the impedance to uterine circulation and hence reduces the effective uterine blood flow after a predetermined period of therapy.
DESIGN: Prospective, longitudinal study.
SETTING: Reproductive medicine unit of a university teaching hospital. PATIENT(S): Eight premenopausal women with dysfunctional uterine bleeding. INTERVENTION(S): Six weeks of danazol therapy. MAIN OUTCOME MEASURE(S): The uterine artery blood flow impedance as indicated by the pulsatility and resistance indices; the hormonal profile (E2, FSH, and LH levels); the uterine dimensions (length, width, anteroposterior diameter, and area); and the endometrial thickness. RESULT(S): The indices of uterine artery impedance were significantly increased after danazol therapy, indicating a possible reduction in the effective uterine artery blood flow. There was no statistically significant change in the hormonal profile, uterine dimensions, or endometrial thickness. CONCLUSION(S): Danazol therapy for 6 weeks results in a significant increase in the uterine artery impedance and hence a possible reduction in the effective uterine artery blood flow. This may explain in part its efficacy in the management of dysfunctional uterine bleeding and in the preoperative preparation of women undergoing endoscopic endometrial ablation. The exact mechanism for its action in this regard remains to be determined but appears to be independent of E2 levels. This preliminary finding may help in monitoring the treatment of dysfunctional uterine bleeding, preoperative and postoperative investigation of women undergoing endoscopic endometrial ablation, and the development of alternative treatment strategies for dysfunctional uterine bleeding in the future.