The FDA's recent approval of over-the-counter status for Plan B has put emergency contraception (EC) on the forefront of the national dialogue. It seems we've got sex -- and everything that follows -- on the brain. Despite all this attention, misunderstandings about Plan B persist. However, there is a tremendous amount of data about the mechanisms, safety and efficacy of this drug that can help to demystify Plan B.
Plan B is the trade name for levonorgestrel, a synthetic form of a reproductive hormone called progesterone. Under normal physiologic conditions, progesterone is involved in regulating the menstrual cycle, suppressing ovulation to maintain pregnancy and orchestrating embryonic development. The hormone's ability to suppress ovulation is utilized in oral contraceptives, which can contain progesterone analogs either alone or in conjunction with estrogen. Specific combinations of these hormones mimic pregnancy, thus preventing egg release. It's sort of a cheap trick, but the body is duped with remarkable consistency -- when used correctly, birth control pills can be up to 99 percent effective at preventing pregnancy.
When used in as an emergency contraceptive, levonorgestrel is given in much higher doses than found in birth control pills. No single mechanism of action has been elucidated for Plan B, in part because the drug's action varies based on when it is taken during the menstrual cycle. The primary function of Plan B in the prevention of pregnancy is believed to be suppression of ovulation. Other reported mechanisms include induction of changes to the uterine lining that prevent implantation of a fertilized egg and interference with egg and sperm transport through the fallopian tubes.
Side effects of Plan B can include nausea, vomiting, dizziness and fatigue. Studies of women who conceived despite taking Plan B have not revealed a tetratogenic effect; in other words, there is not an increased rate of birth defects among babies born to mothers who took the drug. It is recommended that Plan B ideally be taken within 72 hours of unprotected intercourse, although new research supports some effectiveness within a 120 hour interval. However, chances that Plan B will fail still increase with the time that has elapsed since sex (failure rate rises from 4 percent at three days to 10 percent at five days), so rapid availability of the drug is crucial.
Although the public discussion about increasing access to Plan B has been largely couched in ideological terms, the FDA maintains that its hesitation was more about data than dogma. One of their concerns was whether women with home availability of Plan B would use the drug properly in the absence of counseling from a health care provider. Clinical studies have subsequently shown that adult women do use the drug appropriately in this setting. Additionally, risk-taking behavior has not been shown to increase with ease of access to Plan B, another finding supporting easier access to the drug.
So, when sex goes awry ... broken condoms, missed birth control pills, a night you'd rather forget, remember that Plan B is an option. Because when it comes to getting laid, even the best laid plans fall through.
Anne Mills is a Cavalier Daily Health & Sexuality columnist. She can be reached at mills@cavalierdaily.com or through the Sex & Balances submission page at cavalierdaily.com/sex.asp. This column is used for educational purposes only and is not meant to substitute advice from your doctor.
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