From a medical perspective, emergency contraception is safe and effective, although not as effective in preventing pregnancy as routinely used contraceptives. Despite its usefulness in the event of contraceptive lapse or failure, emergency contraception continues to provoke controversy. Central issues leading to debate include the uncertainty of its mechanism of action and, more recently, concerns about the impact of over-the-counter availability, which the U.S. Food and Drug Administration (FDA) denied in its May 2004 decision.

The way emergency contraception prevents pregnancy is not precisely defined, but it likely works by means of several mechanisms, including inhibition of ovulation, prevention of fertilization, and interference with implantation.^1–3 To some persons, any post-fertilization effect is tantamount to abortion. Others, including the FDA, the National Institutes of Health, and the American College of Obstetricians and Gynecologists, define abortion only as disruption of an implanted fertilized ovum. For still others, a precise distinction between prevention of pregnancy and termination of a very early pregnancy is not an important consideration. Clinicians offering emergency contraception must be sensitive to the patient’s perspective on these issues, to their colleagues, and to the policies governing their practice. Patients seeking to make informed decisions on the basis of such definitions should be counseled appropriately.

The controversy becomes more complex when personal and political beliefs mingle with public health advocacy. This situation has occurred in the recent debate over whether emergency contraception should be granted over-the-counter status.⁴ Proponents argue that the United States has a higher rate of unwanted pregnancies than any other developed country. Because emergency contraception has been estimated to prevent potentially one half of these unwanted pregnancies and to halve the abortion rate, they argue that it should be readily available.⁵ Unlike other medications, emergency contraception has a limited window of opportunity during which it is effective, making prompt access a central issue.

Opponents argue that over-the-counter access will deprive users of the benefit of a physician encounter, during which the physician could assess for sexually transmitted diseases, prescribe ongoing contraceptive methods, and provide behavioral counseling. In addition, some opponents state that over-the-counter emergency contraception would encourage high-risk behavior, particularly in adolescents, and increase reliance on this method rather than use of other contraceptive methods. Moreover, they contend that patients would be less likely to use emergency contraception correctly on their own than if properly instructed in an office visit.

The article by Weismiller⁶ in this issue reviews the evidence showing that emergency contraception, which is widely available in Europe without prescription, is used judiciously and properly. Numerous studies have shown that the availability of emergency contraception does not interfere with regular contraception use or lead to overuse. Conversely, there is little evidence that fears and concerns about irresponsible sexual behavior and excessive reliance on emergency contraception are indeed warranted.⁷ It is not known whether over-the-counter availability would reduce physician contact overall or what impact the purported missed contacts might have on clinical outcomes and sexual behavior. To add to the controversy, the findings of two recent European studies suggest that emergency contraception does not reduce abortion rates,^8,9 but the results may only be meaningful in their local settings.

In the final decision about releasing emergency contraception as a nonprescription drug, politics and emotions, rather than available scientific evidence or lack of evidence, may be the decisive factors. For example, the FDA hearings on over-the-counter availability that were conducted in 2000 revealed remarkable distortion of scientific fact by individual speakers, including the claim that in preventing implantation of a fertilized ovum, emergency contraception in nulliparous women results in a breast cancer risk of 50 percent.¹⁰ It also is clear to the medical community that political considerations, rather than scientific evidence, underlie the recent FDA decision to deny over-the-counter status to emergency contraception despite a Joint Advisory Committee recommendation 23 to four favoring over-the-counter access.¹¹

The bottom line is that this method has the potential to reduce the rate of unwanted pregnancies in the United States, without increasing unprotected sex or decreasing reliance on other methods of contraception in adolescents.¹² All women of reproductive age should be able to access it promptly.