"What are birth control pills and how do they work?
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 prevent"...
Progestin-only oral contraceptives are indicated for the prevention of pregnancy.
If used perfectly, the first-year failure rate for progestin-only oral contraceptives is 0.5%. However, the typical failure rate is estimated to be closer to 5%, due to late or omitted pills. Table 1 lists the pregnancy rates for users of all major methods of contraception.
Table 1: Percentage of Women Experiencing an Unintended Pregnancy
During the First Year of Typical Use and the First Year of Perfect Use of Contraception
and the Percentage Continuing Use at the End of the First Year. United States.
|% of Women Experiencing an
Unintended Pregnancy within
the First Year of Use
|% of Women
Continuing Use at
|Method(1)||Typical Use 1(2)||Perfect Use2(3)||(4)|
| Adapted from Hatcher et al, 1998, Ref. #
Emergency Contraceptive Pills: Treatment initiated within 72 hours after unprotected intercourse reduces the risk of pregnancy by at least 75%.9
Lactational Amenorrhea Method: LAM is highly effective, temporary method of contraception.10 Source: Trussell J, Contraceptive efficacy. In Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, Contraceptive Technology: Seventeenth Revised Edition. New York NY: Irvington Publishers, 1998.
1 Among typical couples who initiate use of a method (not necessarily for the first time), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason.
2 Among couples who initiate use of a method (not necessarily for the first time) and who use it perfectly (both consistently and correctly), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason.
3Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year.
4 The percents becoming pregnant in columns (2) and (3) are based on data from populations where contraception is not used and from women who cease using contraception in order to become pregnant. Among such populations, about 89% become pregnant within one year. This estimate was lowered slightly (to 85%) to represent the percent who would become pregnant within one year among women now relying on reversible methods of contraception if they abandoned contraception altogether.
5Foams, creams, gels, vaginal suppositories, and vaginal film.
6 Cervical mucus (ovulation) method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases.
7With spermicidal cream or jelly.
9 The treatment schedule is one dose within 72 hours after unprotected intercourse, and a second dose 12 hours after the first dose. The Food and Drug Administration has declared the following brands of oral contraceptives to be safe and effective for emergency contraception: OvralR (1 dose is 2 white pills), AlesseR (1 dose is 5 pink pills), NordetteR or LevlenR (1 dose is 2 light-orange pills), Lo/OvralR (1 dose is 4 white pills), TriphasilR or Tri-LevlenR (1 dose is 4 yellow pills).
10 However, to maintain effective protection against pregnancy, another method of contraception must be used as soon as menstruation resumes, the frequency or duration of breastfeeds is reduced, bottle feeds are introduced, or the baby reaches six months of age.
ORTHO MICRONOR® (norethindrone) Tablets have not been studied for and are not indicated for use in emergency contraception.
DOSAGE AND ADMINISTRATION
To achieve maximum contraceptive effectiveness, ORTHO MICRONOR® (norethindrone) must be taken exactly as directed. One tablet is taken every day, at the same time. Administration is continuous, with no in terruption between pill packs. See Detailed Patient Labeling for detailed instruction.
ORTHO MICRONOR® (0.35 mg norethindrone) Tablets are available in a DIALPAK® Tablet Dispenser
(NDC 0062-1411-16) containing 28 lime green, round, flat faced, beveled edge tablets, imprinted “ORTHO 0.35” on both sides.
STORAGE: Store at 25°C
Keep out of reach of children.
McCann M, and Potter L. Progestin-Only Oral Contraceptives: A Comprehensive Review. Contraception, 50:60 (Suppl. 1), December 1994.
Truitt ST, Fraser A, Gallo ME, Lopez LM, Grimes DA and Schulz KF. Combined hormonal versus nonhormonal versus progestin-only contraception in lactation (Review). The Cochrane Collaboration. 2007, Issue 3.
Halderman, LD and Nelson AL. Impact of early postpartum administration of progestin-only hormonal contraceptives compared with nonhormonal contraceptives on short-term breast-feeding patterns. Am J Obstet Gynecol.; 186 (6):1250-1258.
Ostrea EM, Mantaring III JB, Silvestre MA. Drugs that affect the fetus and newborn infant via the placenta or breast milk. Pediatr Clin N Am; 51(2004): 539-579.
Cooke ID, Back DJ, Shroff NE: Norethisterone concentration in breast milk and infant and maternal plasma during ethynodiol diactetate administration. Contraception 1985; 31:611-21.
ORTHO-McNEIL, PHARMACEUTICAL, INC., Raritan, New Jersey 08869. REVISED June, 2008. FDA rev date: 6/20/2008
Last reviewed on RxList: 7/24/2008
This monograph has been modified to include the generic and brand name in many instances.
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