Research eyes options in emergency contraception

What if you could simplify your current protocol for emergency contraception (EC)? Results of a recent international multicenter randomized trial indicate that three effective options exist for emergency contraception: two 0.75-mg doses of levonorgestrel 12 hours apart, a single 10-mg dose of mifepristone, or a single 1.5-mg dose of levonorgestrel.1

No matter which drug protocol is used, it is important to get emergency contraception into the hands of women who need it. Access can make an impact: a new analysis by the New York City-based Alan Guttmacher Institute estimates that 51,000 abortions were prevented by EC use in 2000, 47,000 more than in 1994, when only 4,000 abortions were averted through EC. Overall, 110,000 fewer abortions occurred in 2000 than in 1994, meaning that increased use of EC may account for up to 43% of the total decline.2

"Our research demonstrates that emergency contraception did have an impact on abortions between 1994 and 2000," states Rachel Jones, PhD, senior research associate at the institute. "If even more women have knowledge and access to emergency contraception, it is likely that it will have an even greater impact on abortion and specifically will reduce the number of abortions even further."

To compare the different EC regimens, the Geneva-based World Health Organization (WHO), conducted research in 15 family planning clinics in 10 countries. The study included 4,136 healthy women with regular menstrual cycles who requested emergency contraception within five days of unprotected sexual intercourse. Women were randomly assigned to one of three treatment groups: 10-mg single-dose mifepristone; 1.5-mg single-dose levonorgestrel; or two doses of 0.75-mg levonorgestrel given 12 hours apart.

There were no significant differences in pregnancy rates or side effects between the three groups, with an average pregnancy rate of about 1.6%. Most women menstruated within two days of the expected date, although women given levonorgestrel menstruated earlier than women given mifepristone.

"Low dose mifepristone and levonorgestrel regimens had a similar efficacy in our study," notes Helena von Hertzen, MD, medical director of the WHO’s Special Programme of Research, Development, and Research Training in Human Reproduction. "Regarding levonorgestrel, the study showed that the dose does not need to be split, and this simplifies its use."

What is your practice?

U.S. providers choose from two dedicated EC products, Plan B (Women’s Capital Corp., Washington, DC) and Preven (Gynétics, Belle Mead, NJ), or use the Yuzpe regimen employing combined oral contraceptives. In the 2002 Contraceptive Technology Update Contraception Survey, about 66% of providers said they used Plan B, with about 15% prescribing Preven. About 20% said they administered the Yuzpe regimen, using combined oral contraceptives.

Plan B’s current approved dosing regimen is two 0.75-mg tablets of levonorgestrel, with the first pill taken within 72 hours of unprotected sex, followed by the second pill 12 hours later. The Preven regimen is four pills, each containing 0.25-mg levonorgestrel and 0.05-mg ethinyl estradiol; the first dose of two pills is taken within 72 hours of unprotected sex, followed by the second dose of two pills 12 hours later.

Interest is growing in the potential use of mifepristone, marketed in the United States as Mifeprex (Danco Laboratories LLC, New York City) for emergency contraception. In a separate trial conducted in 10 family planning institutes and hospitals in China, women who met recruitment criteria and requested emergency contraception within 120 hours of a single act of unprotected intercourse were randomized to receive 10 mg or 25 mg of mifepristone. Research indicates that the single 10-mg dose of mifepristone is sufficient for emergency contraception.3

Mifepristone received approval from the Food and Drug Administration for use in early medical abortion in September 2000, and distribution of the drug began in November 2000. According to new research from the New York City-based Alan Guttmacher Institute, early medical abortion accounted for 37,000 abortions, or 6% of all abortions, in the first half of 2001.4

Mifepristone for abortion only

While research has shown that mifepristone is an effective EC option,5 the drug’s only approved indication in the United States is for use in early medical abortions. While mifepristone appears to be safe, highly effective, and acceptable for use in emergency contraception, it may be some time before it is used in this context by American providers. Even though the study shows that the three various EC methods were effective in preventing pregnancy, they are much less effective than modern methods of contraception for regular use, says von Hertzen.

"This is why emergency contraception should never be the only method of contraception, even for occasional use, as using it repeatedly is like playing some kind of Russian roulette until unwanted pregnancy occurs," she observes. "Emergency contraception will serve us best as a backup; it gives a second chance to avoid pregnancy."

References

1. von Hertzen H, Piaggio G, Ding J, et al. Low-dose mifepristone and two regimens of levonorgestrel for emergency contraception: A WHO multicentre randomised trial. Lancet 2002; 360:1,803-1,810.

2. Jones RK, Darroch JE, Henshaw SK. Contraceptive use among U.S. women having abortions in 2000-2001. Perspectives on Sexual and Reproductive Health 2002; 34:294-303.

3. Xiao BL, von Hertzen H, Zhao H, et al. A randomized double-blind comparison of two single doses of mifepristone for emergency contraception. Hum Reprod 2002; 17:3,084-3,089.

4. Finer LB, Henshaw SK. Abortion incidence and services in the United States in 2000. Perspectives on Sexual and Reproductive Health 2002; 35:6-15.

5. Task Force on Postovulatory Methods of Fertility Regulation. Comparison of three single doses of mifepristone as emergency contraception: A randomised trial. Lancet 1999; 353:697-702.