title: Pituitary-ovarian activity when switching from various monophasic pills to a triphasic pill.
abstract: This study was prompted by the various recommendations given by different oral contraceptive manufacturers to women who wish to switch from a monophasic to a triphasic formulation. Ten women who switched from a variety of monophasic pills to a levonorgestrel triphasic pill formulation after a 7-day pill-free interval were studied. Follicular maturation was monitored by ultrasound scan, and the levels of serum follicle stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P) and estradiol (E2) measured. Pituitary-ovarian activity was suppressed in six of the ten women studied, while in the remaining four women there was some pituitary-ovarian activity during the first 10 days on the triphasic pill. These findings suggest a shorter pill-free interval, as advised in USA data sheets, may be less likely to result in pill failures when women switch from a monophasic to a triphasic preparation.
authors.affiliation: Department of Obstetrics and Gynaecology, University Hospital of South Manchester, UK.
authors.forename: E
authors.initials: E
authors.lastname: Eyong
authors.forename: A R
authors.initials: AR
authors.lastname: Priddy
authors.forename: S R
authors.initials: SR
authors.lastname: Killick
authors.forename: M
authors.initials: M
authors.lastname: Elstein
mesh_terms: D000293:Adolescent; D000328:Adult; D003277:Contraceptives, Oral, Combined / Q000494:pharmacology; D003278:Contraceptives, Oral, Hormonal / Q000494:pharmacology*; D017135:Desogestrel; D004338:Drug Combinations; D004958:Estradiol / Q000097:blood; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D019304:Ethinyl Estradiol-Norgestrel Combination; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008598:Menstruation; D009640:Norethindrone / Q000494:pharmacology; D009644:Norgestrel / Q000494:pharmacology*; D009652:Norpregnenes / Q000494:pharmacology; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000502:physiology; D010053:Ovary / Q000187:drug effects*; D010902:Pituitary Gland / Q000187:drug effects*; D011374:Progesterone / Q000097:blood; D011372:Progestins / Q000494:pharmacology
chemical_list: D003277:Contraceptives, Oral, Combined; D003278:Contraceptives, Oral, Hormonal; D004338:Drug Combinations; D009652:Norpregnenes; D011372:Progestins; C020416:norethindrone acetate, ethinyl estradiol, ferrous fumarate drug combination; D009644:Norgestrel; D004997:Ethinyl Estradiol; D011374:Progesterone; D004958:Estradiol; D019304:Ethinyl Estradiol-Norgestrel Combination; D017135:Desogestrel; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D009640:Norethindrone