Modification of 24-h ambulatory blood pressure and heart rate during contraception with the vaginal ring: a prospective study

BACKGROUND: Hypertension is recognized as a major risk factor for coronary, cerebral and renal vascular disease. Hormonal methods of contraception may increase the risk for cardiovascular events. We evaluated whether the combined hormonal contraceptive vaginal ring that releases 15-mcg ethinylestradiol and 120 mcg of etonogestrel each day influences 24-h ambulatory blood pressure. STUDY DESIGN: At baseline, ambulatory blood pressure was automatically monitored every 30 min for 41 h in 18 normotensive healthy women during their follicular phase (Days 3-6). Each subject was immediately treated with the vaginal ring for six cycles. Monitoring of ambulatory blood pressure was repeated in the last days of the sixth cycle of treatment. RESULTS: During the vaginal ring, a significant increase was observed for 24-h diastolic (2.75±5.13 mmHg; p=.03) and mean (2.69±5.35 mmHg; p=.048) blood pressure and for daytime diastolic (3.04±6.36 mmHg; p=.05) blood pressure. No variation was found in nighttime blood pressure. Heart rate increased in the 24-h period (3.39±5.85 beats/min; p=.025) and in the daytime (3.38±6.25 beats/min; p=.034) measurements. CONCLUSIONS: In normotensive women, the vaginal ring slightly increases 24-h blood pressure and heart rate. The underlying mechanisms and the clinical impact of these slight modifications require further evaluation.