Effect of "missed" pills on oral contraceptive effectiveness.

Objective: The purpose of this study was to determine whether missing pills in an oral contraceptive (OC) cycle resulted in folliculogenesis and eventual ovulation. Methods: Fifteen women selected from a population requesting tubal reanastomosis were randomized into three groups and issued pill packs missing four consecutive pills in specific sequences, as follows: group I, days 1-4; group II, days 3-6; and group III, days 6-9. Serum was drawn for assay of LH, FSH, estradiol (E2), and progesterone, and serial ovarian ultrasound examinations were done to study follicular development throughout the cycle at 4-day intervals