Objective: To assess uterine artery blood flow and endometrial thickness in postmenopausal patients receiving sequential hormone replacement therapy (HRT) at different phases of the treatment.
Design: Prospective controlled study.
Setting: Ultrasound and menopause units of the obstetrics and gynecology department of the University of Tor Vergata, Rome, Italy.
Patient(s): Forty postmenopausal women were treated with cyclic sequential HRT (transdermal E2, 50 microg/d, days 1-21; and dydrogesterone, 10 mg/d, days 12-24).
Intervention(s): All patients underwent transvaginal color Doppler sonography in the estrogen (phase E) and progestogen (phase E/P) phases and after uterine bleeding when no hormone was administered (phase 0).
Main outcome measure(s): Endometrial thickness; systolic, diastolic, and mean velocities; and pulsatility and resistance indices of the uterine arteries.
Result(s): No statistically significant difference in endometrial thickness between phase E (6.5+/-1.6 mm) and phase E/P (6.0+/-1.7 mm) was observed. In phase 0, compared with phases E and E/P, a statistically significant decrease in endometrial thickness was found (4.1+/-1.2 mm). Doppler flow impedance parameters of uterine arteries during the different phases of the HRT cycle showed no differences between the phases considered.
Conclusion(s): The decrease in endometrial thickness in phase 0 suggests a protective effect of our cyclic sequential regimen on the endometrium. Dydrogesterone does not interfere markedly with the vasodilatory effect of estrogen on uterine arteries.