The effect of the hypoestrogenic state, induced by a GnRH agonist (GnRH-a), on cardiac function in healthy young women, was evaluated by Doppler echocardiography performed before treatment and when serum 17 beta-estradiol levels were suppressed by GnRH-a to 36.7 pmol/L. The following parameters of aortic flow were measured: peak flow velocity, ejection time, and acceleration time. Additional parameters calculated were flow velocity integral, cardiac index, and mean acceleration. The study group included 15 menstruating women, aged 25-42 yr (mean, 33 yr), with symptomatic fibroids, endometriosis, or scheduled for in vitro fertilization, who were treated with a GnRH-a. There were significant decreases in peak flow velocity (99 +/- 11 vs. 86 +/- 11 cm/s; P = 0.0004) and cardiac index (3.0 +/- 0.7 vs. 2.5 +/- 0.5 L/min.m2; P = 0.002). A decrease that did not reach statistical significance was noted in flow velocity integral (18.9 +/- 2.7 vs. 16.5 +/- 3.4 cm; P = 0.07). Mean acceleration was decreased significantly (12.6 +/- 2.6 vs. 10.8 +/- 1.8 m/s.s; P = 0.01), but no significant changes in acceleration time (81 +/- 16 vs. 83 +/- 10 ms; P = 0.7) or ejection time (296 +/- 25 vs. 295 +/- 27 ms; P = 0.8) were observed. These results indicate that estrogen deprivation is associated with smaller stroke volume and flow acceleration and might suggest that hypoestrogenism has a direct effect on cardiovascular performance.