Birth control pills - overview
Birth control pills (BCPs) contain man-made forms of 2 hormones called estrogen and progestin. These hormones are made naturally in a woman's ovaries. BCPs can contain both of these hormones, or have progestin only.
Both hormones prevent a woman's ovary from releasing an egg during her menstrual cycle (called ovulation). They do this by changing the levels of the natural hormones the body makes.
Progestins also make the mucus around a woman's cervix thick and sticky. This helps prevent sperm from entering the uterus.
Contraception - pills - hormonal methods; Hormonal birth control methods; Birth control pills; Contraceptive pills; BCP; OCP; Family planning - BCP; Estrogen - BCP; Progestin - BCP
BCPs are also called oral contraceptives or just "the pill." A health care provider must prescribe BCPs.
All women who take BCPs need a check-up at least once a year. Women should also have their blood pressure checked 3 months after they begin to take the pill.
BCPs only work well if the woman remembers to take her pill daily without missing a day. Only 2 or 3 women out of 100 who take BCPs correctly for a year will get pregnant.
BCPs may cause many side effects. These include:
Rare but dangerous risks from taking BCPs include:
BCPs without estrogen are much less likely to cause these problems. The risk is higher for women who smoke or have a history of high blood pressure, clotting disorders, or unhealthy cholesterol levels. However, the risks of developing these complications are much lower with either type of pill than with pregnancy.
Regular menstrual cycles will return within 3 to 6 months after a woman stops using most hormonal birth control methods.
Glasier A. Contraception. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 134.
Harper DM, Wilfling LE, Blanner CF. Contraception. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 26.
Rivlin K, Westhoff C. Family planning. In: Lobo RA, Gershenson DM, Lentz GM, Valea FA, eds. Comprehensive Gynecology. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 13.
Winikoff B, Grossman D. Contraception. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 238.
Review Date: 1/14/2018
Reviewed By: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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