Endothelial function, endothelin-1, and fibrinogen in young women using the vaginal contraceptive ring.

OBJECTIVE: To assess the effects of the vaginal contraceptive ring cycle on indices of cardiovascular health and risk by studying healthy women during the active hormone phase compared with the ring-free phase of a standard 21/7-day cycle.
DESIGN: Observational prospective cohort; 4 weeks' duration.
SETTING: Department of Human Physiology, University of Oregon. PATIENT(S): Twenty healthy women. INTERVENTION(S): Endothelial function testing using standard flow-mediated vasodilation of the brachial artery and sublingual nitroglycerin administration. All participants underwent venous blood collection. MAIN OUTCOME MEASURE(S): Endothelium-dependent and endothelium-independent vasodilation of the brachial artery using Doppler ultrasound imaging. Baseline levels of high-density lipoprotein, low-density lipoprotein, triglycerides, total cholesterol, endothelin-1, and fibrinogen. RESULT(S): The active hormone phase of the vaginal ring cycle showed significantly higher vasodilation compared with the ring-free phase. The active hormone phase also showed increased fibrinogen levels compared with the ring-free phase. Low-density lipoprotein lipid levels also fluctuated and were significantly higher during the ring-free phase. CONCLUSION(S): Preliminary study observations of improved endothelial function and lowered low-density lipoprotein levels during the active hormone phase versus the ring-free phase suggest that the vaginal contraceptive ring has beneficial effects on vascular health in women.