Continuous LNG/EE, a low-dose continuous-use oral contraceptive, provides similar efficacy and safety to a monthly cyclic oral contraceptive.

¹Frauenklinik, Klinikum Aschaffenburg, Aschaffenburg, Germany, ²Gaubius Laboratory, TNO Quality of Life, Biomedical Research, Leiden, Netherlands, ³Research Headquarters, Wyeth Research, Collegeville, PA, United States, ⁴Wyeth Research, Paris, France 

Objective The efficacy of continuous LNG/EE (levonorgestrel 90 µg/ethinyl estradiol 20 µg) was assessed and the safety of this novel low-dose continuous oral contraceptive (OC) was compared to that of a 21-day cyclic OC. 

Study Design and Methods Healthy, sexually active women aged 18 to 49 years (N = 641) with a 3-month history of regular menstrual cycles participated in this phase 3, randomized, 1-year (ie, 13 pill packs), open-label, multicenter study conducted in Europe to compare the efficacy and safety of continuous LNG/EE taken daily without a hormone-free interval, with that of a 21-day cyclic OC (LNG 100 µg/ EE 20 µg). Subjects recorded vaginal bleeding on daily diary cards with bleeding and spotting defined according to WHO standard definitions. 

Results There were no pregnancies among women taking continuous LNG/EE (n = 323), and 3 pregnancies among those taking the 21-day cyclic OC (n = 318). Over time, a majority of women taking continuous LNG/EE reported amenorrhea (27.1%, 39.6%, and 52.9% of subjects at pill packs 3, 7 and 13, respectively). The number of women requiring any sanitary protection during the pill pack gradually decreased with continuous LNG/EE (49.7%, 31.3%, and 21.0% at pill packs 3, 7, and 13, respectively). Women in the 2 groups reported a similar incidence of adverse events (AEs). Bleeding-related AEs (menorrhagia, metrorrhagia, and vaginal bleeding) were more common with continuous LNG/EE during pill packs 1 through 6, but were not different between the 2 groups during pill packs 7 through 13. In contrast, nausea and breast pain were similar between the 2 groups during pill packs 1 through 6, but were significantly less common with continuous LNG/EE during pill packs 7 to 13 (P <0.05). 

Conclusion Continuous LNG/EE offers similar safety to that of a 21-day cyclic OC, and gradually provides amenorrhea or no bleeding for most women.