title: Effect of "missed" pills on oral contraceptive effectiveness.
abstract: 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.
  
  
  RESULTS
  No subject ovulated, as suggested by serum progesterone concentrations (not exceeding 0.63 ng/mL for any woman) and ultrasound assessment of follicular development (no follicular diameter exceeding 13 mm). The highest (mean +/- standard deviation) serum concentrations of LH and FSH in any group (13.25 +/- 18.71 and 14.40 +/- 7.71 mIU/mL, respectively) and of E2 (44.35 +/- 26.79 pg/mL) were observed during or immediately after the pill-free interval. Ovarian ultrasound examinations suggested suppressed folliculogenesis in all groups. No functional ovarian cysts were detected.
  
  
  CONCLUSIONS
  Oral contraceptives exerted a similar degree of pituitary and ovarian suppression even when the subjects missed four pills at varying times in a cycle. The anovulatory effect persisted when the OC pills were reinstituted and taken reliably after an interval of noncompliance.
authors.affiliation: Department of Obstetrics and Gynecology, Tripler Army Medical Center, Honolulu, Hawaii.
authors.forename: G S
authors.initials: GS
authors.lastname: Letterie
authors.forename: G E
authors.initials: GE
authors.lastname: Chow
mesh_terms: D000328:Adult; D003279:Contraceptives, Oral, Sequential / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology*; D010349:Patient Compliance; D011897:Random Allocation
chemical_list: D003279:Contraceptives, Oral, Sequential; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone