OBJECTIVE: Our purpose was to determine whether aortic size and compliance are altered by an exogenously induced rise in estrogen.

STUDY DESIGN: Magnetic resonance imaging was used to determine the aortic cross-sectional area/aortic pressure relationship in nine premenopausal women before and after menotropin therapy. Simultaneous electrocardiograms, carotid pulse tracings, phonocardiograms, and brachial artery pressures were obtained before each magnetic resonance imaging acquisition. Ascending thoracic aorta cross-sectional area was obtained every 32 msec and aligned with brachial artery pressures extrapolated from the carotid pulse tracing, allowing construction of the ascending thoracic aorta cross-sectional area/aortic pressure relationships. Aortic cross-sectional area was normalized to body surface area, and the shifts in the position for the ascending thoracic aorta cross-sectional area/aortic pressure relationship were determined with use of analysis of covariance.

RESULTS: Heart rate and aortic pressure were unchanged before and after menotropin treatment. Initial estradiol levels were <20 pg/ml. After menotropin treatment (7.4 ± 1.0 days) estradiol levels rose to 905 ± 371 pg/ml (p < 0.0001). Ascending thoracic aorta cross-sectional area/body surface area was not significantly increased, adjusted y mean of 389 ± 7 mm²/m² before and 403 ± 7 mm²/m² after menotropin treatment (p < 0.24). The slope of the ascending aorta cross-sectional area/aortic pressure relationship, an index of aortic compliance, increased from 1.4 ± 0.6 mm²/m²/mm Hg before to 1.7 ± 0.6 mm²/m²/mm Hg after menotropin treatment (p < 0.001).

CONCLUSION: In premenopausal women a short-term rise in estrogen induced by menotropin treatment is associated with an increase in aortic compliance. Aorta size is not significantly increased within this time frame. (Am J Obstet Gynecol 1997;176:1255-61.)