RELATIONSHIPS BETWEEN BLOOD-PRESSURE, ORAL-CONTRACEPTIVE USE AND METABOLIC RISK MARKERS FOR CARDIOVASCULAR-DISEASE

Data from a previous study, designed to compare metabolic risk markers for cardiovascular disease in non-users and oral contraceptive (OC) u sers, were analysed to evaluate the influence of OC composition on blo od pressure. Healthy, female volunteers (1189 women) either not using OC (non-users) or currently using one of six different combined formul ations (users) were compared. Combinations studied contained 30-40 mu g ethinyl estradiol combined with the progestins levonorgestrel, noret hindrone (at two and three different doses, respectively) or desogestr el. After statistical standardisation to account for the significantly greater age of the non-users and longer duration of OC use amongst th e levonorgestrel combination users, mean blood pressure was higher, co mpared with non-users, in users of monophasic or triphasic levonorgest rel combinations (systolic: + 4.3 mmHg (p < 0.001) and + 2.7 mmHg (p < 0.0001, respectively; diastolic: + 2.6 mmHg (p < 0.001) and + 2.3 mmH g (p < 0.05), respectively. Blood pressures in users of monophasic nor ethindrone and desogestrel combinations were not significantly raised and there was no increase in the proportion of women with abnormal val ues. 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-user s. Currently used OC containing norethindrone or desogestrel progestin s have little impact on blood pressure. Their correlated reduction in impact on insulin concentrations, though small, suggests common mechan isms through which OC affect blood pressure and insulin.