Birth control pills come in a variety of formulations. The main division is betweencombined oral contraceptive pills, containing bothestrogens andsyntheticprogestogens (progestins), andprogestogen only pills. Combined oral contraceptive pills also come in varying types, including varying doses of estrogen, and whether the dose of estrogen or progestogen changes from week to week.
Combination pills usually work by preventing theovaries from releasing eggs (ovulation). They also thicken thecervical mucus, which keepssperm from penetrating into the uterus and joining with anegg. The hormones in combination and progestogen-only pills also thin the lining of theuterus. This could preventpregnancy by interfering with implantation of ablastocyst.
Main action in typical use is prevention of ovulation.
All contain an estrogen,ethinylestradiol ormestranol,[1][2] in varying amounts, and one of a number of different progestogens. (Regarding the estrogen, the inactive 3-methyl ether of ethinylestradiol, which must be metabolized by the liver into the active ethinylestradiol; 50 μg of mestranol is equivalent to only 35 μg of ethinylestradiol and should not be used when high-dose [50 μg ethinylestradiol] estrogen pills are needed; mestranol was the estrogen used in the first oral contraceptive,Enovid). They are usually taken for 21 days with then a seven-day gap during which a withdrawal bleed (often, but incorrectly, referred to as amenstrual period) occurs. These differ in the amount of estrogen given, and whether they are monophasic (the same dose of estrogen and progestogen during each of the 21 days) or multiphasic (varying doses). The introduction ofextended-cycle monophasic pills (i.e. Seasonale) has shown that the withdrawal bleeding intervals can be decreased.
In 2023, the combination ethinylestradiol/norgestrel was the 282nd most commonly prescribed medication in the United States, with more than 700,000 prescriptions.[3][4]
These are typically given as 21 tablets of estrogen and progestogen, followed by seven tablets of placebo or aniron supplement,[5][6] although some newer formulations contain more active tablets and fewer placebos. Everyday regimens (Microgynon 30 ED, Femodene ED, Logynon ED), which include seven inactive placebo pills, are rarely used in UK practice.[7] Different formulations contain different amounts of estrogen and progestogen:
15 μg ethinylestradiol
60 μggestodene: 24 days + 4 days placebo (Spain: Melodene-15; Israel: Minesse)[8]
3000 μgdrospirenone: 24 days + 4 days placebo (US, EU, RU: Yaz; Bayer Schering Pharma AG. Cleonita); 21 days + 7 days placebo (US, EU:Yasminelle, Bayer); 24 days + 4 days placebo and levomefolate calcium (RU: Yaz Plus, US:Beyaz; Bayer)
ethinylestradiol/norgestimate combination with 7 tablets 25 μg/180 μg, 7 tablets 25 μg/215 μg, 7 tablets 25 μg/250 μg followed by 7 placebos (Ortho Tri-Cyclen Lo from Ortho-McNeil, Tri-Lo Sprintec back from Teva, Tri-Lo Marzia from Lupin, and norgestimate/ethinylestradiol from Mylan)[11]
ethinylestradiol/desogestrel combination with 7 tablets 25 μg/100 μg, 7 tablets 25 μg/125 μg, 7 tablets 25 μg/150 μg, followed by 7 tablets offerric oxide (US: Cyclessa, Organon; Velivet, Barr)
20/30/35 μg ethinylestradiol: estrophasic
ethinylestradiol/norethisterone acetate combination with 5 tablets 20 μg/1000 μg, 7 tablets 30 μg/1000 μg, 9 tablets 35 μg/1000 μg, followed by 7 tablets of ferrous fumarate 75 mg (US:Estrostep Fe, Warner Chilcott)
Progestogen-only pills (POPs) use aprogestogen alone with doses taken continuously and no or a short gap between packs taken. People who use them may experience irregular light bleeds, and whilst irregular in the first few months of taking, usually settles to a regular pattern in time.
Generally oral contraceptives should not be used in people who currently have the following conditions:
Thrombophlebitis or thromboembolic disorders
A history of deep vein thrombophlebitis or thromboembolic disorders
Cerebrovascular or coronary artery disease (current or history)
Valvular heart disease with thrombogenic complications
Severe hypertension
Diabetes with vascular involvement
Headaches with focal neurological symptoms
Major surgery with prolonged immobilization
Known or suspected carcinoma of the breast or personal history of breast cancer
Carcinoma of the endometrium or other known or suspected estrogen-dependent neoplasia
Undiagnosed abnormal genital bleeding
Cholestatic jaundice of pregnancy or jaundice with prior pill use
Hepatic adenomas or carcinomas, or active liver disease
Known or suspected pregnancy
Hypersensitivity to any component of the product
More comprehensive guidelines that include analysis of risks and benefits can be found in the World Health Organization Medical Eligibility for Contraceptive Use Guidelines[14] which are reflected in theCDC Medical Eligibility for Contraceptive Use Guidelines.[15]
^Hatcher, Robert A., Nelson, Anita (2004). "Combined Hormonal Contraceptive Methods". In Hatcher, Robert A. (eds.).Contraceptive Technology (18th rev. ed.). New York: Ardent Media. pp. 391–460.ISBN0-9664902-5-8.
^Speroff, Leon, Darney, Philip D. (2005). "Oral Contraception".A Clinical Guide for Contraception (4th ed.). Philadelphia: Lippincott Williams & Wilkins. pp. 21–138.ISBN0-7817-6488-2.
^Serge Herceberg, Paul Preziosi, Pilar Galan."Iron deficiency in Europe"(PDF). Public Health Nutrition: 4(2B). pp. 537–545. Archived fromthe original(PDF) on 26 July 2011. Retrieved19 November 2010.
