Functional life-span of the dominant follicle in pharmacologically induced anovulatory cycles.

With the purpose of measuring the duration of the functional life-span (FLS) of the anovulatory follicle in women under continuous low-dose progestogen treatment, the oestradiol curve of Norplant implant users was retrospectively analysed. From all the data collected during the previous 5 years at the Department of Biomedical Research at the Family Planning Clinic of Profamilia, Santo Domingo, Dominican Republic, data from all 29 Norplant implant users showing follicular activity without luteal activity were selected for this retrospective analysis. Serial blood sampling twice or three times a week for 5 or 6 consecutive weeks had been taken in all subjects. The duration of the FLS of the dominant follicle in anovulatory cycles was defined at the period from the first day of ascending oestradiol curve until the day preceding onset of menses. The mean FLS of the dominant follicle in anovulatory cycles under continuous low-dose progestogen administration was 21.1 +/- 4.2 days, independently of the length of the menstrual cycle. The duration of the FLS of the anovulatory dominant follicle appears not to be different from the duration of a normal follicle/corpus luteum unit.