Oral contraceptives and blood pressure.

Both cross-sectional and longitudinal analysis of data from 13,358 women showed that oral contraceptive use is associated with a slight but statistically significant (P lesser than .05) rise in mean blood pressure, which is reversible. The age-adjusted proportion of oral contraceptive users with a blood pressure over 140/90 mm Hg was about three times that on nonusers. These findings are caused by a uniform upward shift in the blood pressure distribution of oral contraceptive users compared to nonusers. Women continuing oral contraceptive use had no appreciably greater change in blood pressure between two visits than persistent nonusers. The clinical implications of a mild contraceptive-induced blood pressure elevation (systolic, 5 to 6 mm Hg; diastolic, 1 to 2 mm Hg) remain unsettled but disturbing.