Data from a previous study, designed to compare metabolic risk markers for cardiovascular disease in non-users and oral contraceptive (OC) users, were analysed to evaluate the influence of OC composition on blood pressure. Healthy, female volunteers (1189 women) either not using OC (non-users) or currently using one of six different combined formulations (users) were compared. Combinations studied contained 30-40 micrograms ethinyl estradiol combined with the progestins levonorgestrel, norethindrone (at two and three different doses, respectively) or desogestrel. After statistical standardisation to account for the significantly greater age of the non-users and longer duration of OC use amongst the levonorgestrel combination users, mean blood pressure was higher, compared with non-users, in users of monophasic or triphasic levonorgestrel combinations (systolic: +4.3 mmHg (p < 0.001) and +2.7 mmHg (p < 0.001), respectively; diastolic: +2.6 mmHg (p < 0.001) and +2.3 mmHg (p < 0.05), respectively). Blood pressures in users of monophasic norethindrone and desogestrel combinations were not significantly raised and there was no increase in the proportion of women with abnormal values. Diastolic and systolic blood pressures were positively associated with oral glucose tolerance test insulin response (r = 0.11 (p < 0.01) and r = 0.15 (p < 0.001), respectively) in users but not in non-users. Currently used OC containing norethindrone or desogestrel progestins have little impact on blood pressure. Their correlated reduction in impact on insulin concentrations, though small, suggests common mechanisms through which OC affect blood pressure and insulin.
PIP: The influence of oral contraceptive (OC) composition on blood pressure was investigated in 1189 healthy volunteers recruited from centers in London and southeast England. The mean age of the non-users was 32.5 years compared with 28.0 years among OC users. The OC users were currently taking one of six types of combined OCs containing 30-40 mcg of ethinyl estradiol combined with the progestins levonorgestrel (150 mcg or a 50-125 mcg triphasic), norethindrone (500 mcg, 1000 mcg, or a 500-1000 mcg triphasic), and desogestrel (150 mcg). After adjustment for age and duration of OC use, mean blood pressure was significantly higher compared to non-users in users of monophasic or triphasic levonorgestrel combinations (systolic, +4.3 and +2.7 mm Hg, respectively; diastolic, +2.6 and +2.3 mm Hg, respectively). There was no significant increase in blood pressure levels in users of monophasic norethindrone and desogestrel combinations. Diastolic and systolic blood pressures were significantly positively associated with oral glucose tolerance test insulin responses (r = 0.11 and -0.15, respectively) in OC users but not in non-users. These findings suggest that currently used low-estrogen dose OCs containing norethindrone or desogestrel have little effect on blood pressure. They further indicate that the typical profile recorded in OC users--elevated blood pressure, increased triglycerides, decreased high density lipoprotein cholesterol, increased insulin concentrations, and reduced insulin sensitivity--mainly reflect the independent effects of the contraceptive steroids rather than a single coordinated disturbance.