Birth Control Pills (Oral Contraceptives) (cont.)

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There are different types of combination birth control pills that contain estrogen and progestin that are referred to as "monophasic," "biphasic," or "triphasic."

  • Monophasic birth control pills deliver the same amount of estrogen and progestin every day.

  • Biphasic birth control pills deliver the same amount of estrogen every day for the first 21 days of the cycle. During the first half of the cycle, the progestin/estrogen ratio is lower to allow the lining of the uterus (endometrium) to thicken as it normally does during the menstrual cycle. During the second half of the cycle, the progestin/estrogen ratio is higher to allow the normal shedding of the lining of the uterus to occur.

  • Triphasic birth control pills have constant or changing estrogen concentrations and varying progestin concentrations throughout the cycle. There is no evidence that bi- or triphasic oral contraceptives are safer or superior to monophasic oral contraceptives, or vice versa, in their effectiveness for the prevention of pregnancy.


GENERIC AVAILABLE: Yes, for some (see below)

PREPARATIONS: Tablets, various amounts (Please see the birth control article for non-oral contraceptives.)

STORAGE: All oral contraceptives should be stored between 15 C (59 F) and 30 C (86 F).

PRESCRIBED FOR: Birth control pills are prescribed to prevent pregnancy. When taken as directed, birth control pills fail in less than one in every 200 users over the first year of use.

Birth control pills also are prescribed to treat mid-cycle pain, which some women experience with ovulation. Birth control pills, while regulating the menstrual cycle, reduce menstrual cramps and heavy bleeding, and because of the reduced bleeding, they may prevent the anemia that can develop in some women. For this reason, they also are sometimes prescribed for a number of conditions that are characterized by excessive bleeding or painful menses.

Doctors sometimes prescribe higher doses of birth control pills for use as a "morning after" pill to be taken up to 72 hours after unprotected intercourse to prevent fertilization and pregnancy.

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