title: Extending the duration of the pill-free interval during combined oral contraception.
abstract: The effect of increasing the duration of the pill-free interval from 7 to 9 and 11 days during the first 4 months of combined oral contraceptive therapy was studied by hormonal, ovarian follicle and mucus changes. Increasing the pill-free interval allowed more follicular development and more estradiol production. In some cases, pre-ovulatory values were achieved although ovulation did not occur. No differences could be detected between different types of combined oral contraceptive, including monophasic, triphasic, levonorgestrel-containing and gestodene-containing. The variation between individuals in the group of 28 was far greater than any variation in dose.
authors.affiliation: University Hospital of South Manchester, West Didsbury.
authors.forename: S R
authors.initials: SR
authors.lastname: Killick
authors.forename: K
authors.initials: K
authors.lastname: Bancroft
authors.forename: S
authors.initials: S
authors.lastname: Oelbaum
authors.forename: J
authors.initials: J
authors.lastname: Morris
authors.forename: M
authors.initials: M
authors.lastname: Elstein
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D002582:Cervix Mucus / Q000187:drug effects / Q000502:physiology; D003277:Contraceptives, Oral, Combined / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D005498:Follicular Phase / Q000502:physiology*; D006801:Humans
chemical_list: D003277:Contraceptives, Oral, Combined; D004958:Estradiol