Occurrence of menses or pregnancy after cessation of a continuous oral contraceptive.

Objective: To evaluate the time to return to spontaneous menses in women after 1 year of daily continuous levonorgestrel (LNG) 90 microg/ethinyl E(2) (EE) 20 microg.

Design: Observational study.

Setting: Gynecologic and primary care practices.

Patient(s): Women aged 18-49 years with a history of regular menstrual cycles. After participation in an open-label, continuous oral contraceptive (OC) trial for at least 6 months, participants agreed to enroll in a separate study of the return to menses or pregnancy.

Intervention(s): None.

Main Outcome Measure(s): Time to return to spontaneous menses or pregnancy.

Result(s): The 198 subjects had a mean age of 30.4 +/- 6.6 years with 72% white, 13% Hispanic, and 7% African American. The mean duration of continuous LNG/EE treatment before enrollment was 349 +/- 41 days. Of the 187 (94%) subjects who completed this study, 181 returned to spontaneous menses and 4 became pregnant within 90 days after the last dose of LNG 90 microg/EE 20 microg. The median time to return to menses in the completer population was 32 days, and the incidence of spontaneous menses or pregnancy at day < or = 90 was 98.9%. The duration of amenorrhea during continuous LNG/EE use before stopping treatment was unrelated to the time to the return to menses.

Conclusions: Spontaneous menses or pregnancy occurred in 98.9% of women after cessation of continuous LNG/EE.