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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adolescent
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Adult
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Contraceptives, Oral, Combined / pharmacology
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Contraceptives, Oral, Hormonal / pharmacology*
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Desogestrel
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Drug Combinations
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Estradiol / blood
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Ethinyl Estradiol / pharmacology*
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Ethinyl Estradiol-Norgestrel Combination
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Female
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Follicle Stimulating Hormone / blood
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Humans
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Luteinizing Hormone / blood
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Menstruation
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Norethindrone / pharmacology
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Norgestrel / pharmacology*
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Norpregnenes / pharmacology
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Ovarian Follicle / anatomy & histology
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Ovarian Follicle / physiology
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Ovary / drug effects*
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Pituitary Gland / drug effects*
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Progesterone / blood
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Progestins / pharmacology
Substances
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Contraceptives, Oral, Combined
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Contraceptives, Oral, Hormonal
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Drug Combinations
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Norpregnenes
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Progestins
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norethindrone acetate, ethinyl estradiol, ferrous fumarate drug combination
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Norgestrel
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Ethinyl Estradiol
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Progesterone
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Estradiol
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Ethinyl Estradiol-Norgestrel Combination
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Desogestrel
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Luteinizing Hormone
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Follicle Stimulating Hormone
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Norethindrone