OCs don't seem to increase risk of MI . . .

November 12, 2007

. . . at least according to this new study, which is one of the few population-based, prospective studies to look at the relationship. Involving over 48,000 Swedish women, the investigation looked at primarily 15+ years of use of oral contraceptives (OCs) containing low-dose estrogen and second- or third-generation progestins. Most prospective studies examining the relationship between cardiovascular events and OCs examined use in the 1970s and 1980s, when pills contained higher amounts of estrogen and were clearly associated with an elevated myocardial infarction (MI) risk among users who smoked cigarettes.

. . . at least according to this new study, which is one of the few population-based, prospective studies to look at the relationship. Involving over 48,000 Swedish women, the investigation looked at primarily 15+ years of use of oral contraceptives (OCs) containing low-dose estrogen and second- or third-generation progestins. Most prospective studies examining the relationship between cardiovascular events and OCs examined use in the 1970s and 1980s, when pills contained higher amounts of estrogen and were clearly associated with an elevated myocardial infarction (MI) risk among users who smoked cigarettes.

But, in this latest study, compared with never-users of the pills, neither former (RR 1.0; 95% CI, 0.7-1.4) nor current (RR 0.7; 95% CI, 0.4-1.4) users had an increased risk for future MI.

Whether such a relationship exists is important, particularly in light of the fact that more middle-aged Swedish women (aged 40 to 44), who are already at higher risk for MI just by virtue of their age, are using OCs; while only 4% of women in this age bracket reported use in 1995, 14% reported use in 2002. Thus, even a modestly elevated risk could have profound health implications.

Margolis KL, Adami HO, Luo J, et al. A prospective study of oral contraceptive use and risk of myocardial infarction among Swedish women. Fertil Steril. 2007;88:310-316.