The role of triphasic levonorgestrel in oral contraception: a review of metabolic and hemostatic effects.

ABSTRACT

PIP: This review of studies published since 1985 on the metabolic effects of triphasic levonorgestrel in oral contraceptives (OCs) reveals that triphasic levonorgestrel tends not to affect lipid metabolism. Specifically, it does not significantly change the level of the lipids associated with increased vascular risk (low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), and lipid ratios). Overall, triphasic levonorgestrel OCs do not affect triglycerides, while other OCs increase the level of triglycerides. They also have a lower effect on lipid metabolism than do monophasic levonorgestrel OCs. About 50% of the studies suggest that triphasic levonorgestrel OCs do not affect carbohydrate metabolism, while the remaining studies suggest that they cause a significant increase in carbohydrates. Some studies found that triphasic levonorgestrel OCs impair glucose tolerance. Studies on the effect of triphasic levonorgestrel on hemostasis are less numerous than those on lipid and carbohydrate metabolism. Unlike all combined monophasic OCs, triphasic levonorgestrel OCs appear to have a balanced effect on hemostasis. In fact, they stimulate both the coagulant and anti-coagulant-fibrinolytic pathways. Many of the researchers who found statistically significant metabolic interactions found that the changes fell within the normal clinical range and therefore did not increase the risk of cardiovascular disease. Triphasic levonorgestrel OCs tend to have less of a metabolic effect than its monophasic counterpart and a metabolic effect similar to other low-dose OCs.