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Information on Birth Control Pills »
Birth control pills are also known as oral contraceptives (OCs) or, simply, “the pill.” They offer protection against pregnancy by blocking the union of sperm and egg, thereby preventing conception.
Oral contraceptives or birth control pills contain synthetic female hormones. They work largely by preventing the release of an egg from an ovary, or ovulation. If no egg is released, there can be no pregnancy.
Stopping ovulation is not the only way birth control pills can work. The progestin or synthetic progesterone in birth control pills also changes the physical and chemical environment of the female reproductive tract, making it hostile for sperm.
The active ingredients in birth control pills are synthetic versions of the female hormones estrogen and progesterone. Combination oral contraceptives are birth control...
ORTHO MICRONOR® (norethindrone) progestin-only oral contraceptives prevent conception by suppressing ovulation in approximately half of users, thickening the cervical mucus to inhibit sperm penetration, lowering the midcycle LH and FSH peaks, slowing the movement of the ovum through the fallopian tubes, and altering the endometrium.
Serum progestin levels peak about two hours after oral administration, followed by rapid distribution and elimination. By 24 hours after drug ingestion, serum levels are near baseline, making efficacy dependent upon rigid adherence to the dosing schedule. There are large variations in serum levels among individual users. Progestin-only administration results in lower steady-state serum progestin levels and a shorter elimination half-life than concomitant administration with estrogens.
Last reviewed on RxList: 7/24/2008
This monograph has been modified to include the generic and brand name in many instances.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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