International clinical experience with a new low-dose, monophasic oral contraceptive containing levonorgestrel 100 mu g and ethinyl estradiol 20 mu g

Manufacturers have steadily been decreasing the amounts of estrogen and pro gestin in oral contraceptives (OCs) in an effort to enhance safety and tole rability while preserving contraceptive efficacy. A new formulation contain ing 20 mu g ethinyl estradiol (EE) and 100 mu g levonorgestrel (LNG)-repres enting the lowest available contraceptive dose of each hormone-has undergon e extensive clinical testing in the United States and Germany. A total of 1 590 women in 61 centers received 20 mu g EE and 100 mu g LNG for 6 cycles. Overall, 4 pregnancies possibly related to treatment failure were reported, reflecting an overall Pearl Index (number of pregnancies per 100 woman-yea rs of treatment) of 0.65 and a failure rate of 0.34%. Cycle control was typ ical of low-dose OC use. Spotting and breakthrough bleeding occurred most c ommonly during the earlier cycles in each study. Adverse events were typica l of those seen with OC use and led to study discontinuation in 6.6% of the women. Intermenstrual bleeding was the cause for early study withdrawal in 2.6% of women. The study results suggest that the combination of 20 mu g E E and 100 mu g LNG offers the benefits of low hormone content with good con traceptive efficacy, cycle control, and tolerability.