Metabolic effects of implantable steroid contraceptives for women.

The metabolic impact of progestin-only contraceptives is less than that of combined oral contraceptives. Subdermal contraceptive implant systems that provide a sustained release of low levels of progestins are now becoming widely available. This review evaluates the metabolic effects of currently available products that release the progestins levonorgestrel (Norplant, Jadelle, and their Chinese equivalents); etonogestrel (Implanon); nomegestrol acetate (Uniplant); and Nestorone, formally called ST-1435 (Nestorone implant/Elcometrine). Data on liver, kidney, and renal function; carbohydrates and insulin release; hemostasis; blood pressure; and lipids are considered. The metabolic effects reported for these methods as a whole were minimal. Any changes were generally within the normal range for the populations studied and, therefore, are unlikely to be of clinical significance. However, all published studies have been conducted in healthy populations of women. To inform clinical practice, the field would be well served to have additional empiric data from well-designed, well-implemented, and well-reported trials in women who are deemed to be at elevated risk for certain diseases including cardiovascular disease and diabetes.