Prevention of Ovulation Achieved by Single Intra-vaginal Administration of Levogel as Compared to Oral LNG

It has been proposed that levonorgestrel (LNG) in a vaginal gel could be used as an 'on demand' contraceptive when used before coitus. Levonorgestrel was selected as it is a component of many approved oral contraceptive pills and also it is the active agent in Plan B, an FDA-approved regimen for emergency contraception (EC). In previous studies it was demonstrated that an LNG vaginal gel was absorbed and was effective in preventing follicular rupture. The overall proportion of cycles with lack of follicular rupture within 5 days of LNG administration or with ovulatory dysfunction (follicle rupture preceded by an inadequate LH surge) was 96% for LNG gel and 39% in the inert gel cycles (control group).