Single-Dose Emergency Contraception Effective in Victims of Sexual Assault

Women who reported to the emergency department after sexual assault and were given single-dose levonorgestrel emergency contraception had a very low rate of pregnancy, indicating that the contraception is effective at preventing pregnancy, according to the results of a study conducted in South Korea.

“An unintended pregnancy resulting from sexual assault poses tremendous mental and physical health trauma to the victim,” wrote researchers led by Dong Seok Choi, of Ajou University School of Medicine, Korea. “Emergency contraception provides a safe method of postcoital contraception that could reduce sexual assault-related pregnancies by 88% to 95% if offered within a 120-hour window of the assault.”

Prior studies of emergency contraception have shown that levonorgestrel, 0.75 mg, given twice, 12 hours apart, is effective at preventing pregnancy. However, this dose can be inconvenient when the first dose is given in the afternoon. This study was the first to look at the efficacy of levonorgestrel when given as a single 1.5-mg dose.

Choi and colleagues undertook a retrospective chart review of 1,179 women who visited the emergency department for sexual assault between November 2006 and November 2009. Of these women, 416 had a gynecological examination. The researchers excluded women who were pre-menarche, post-menopausal, already pregnant, or who were not penetrated during the assault. Excluding an additional 43 patients who were aged 45 years or older, 302 received the 1.5-mg levonorgestrel emergency contraception, most within 72 hours. Ten patients did not return for follow-up.

All patients had a pregnancy test conducted during the initial visit and again 3 to 6 weeks after the assault. Two patients had positive pregnancy tests at the follow-up visit, translating into a pregnancy rate of 0.66%. Excluding the 10 patients who did not return for follow-up, the real pregnancy rate was 0.68%, or 2 of 292 women.

“Our study demonstrates that a single 1.5-mg dose of levonorgestrel as emergency contraception after an act of sexual assault is highly effective,” the researchers wrote. “Although this study has certain limitations, it confirms the recommendation that all patients seeking care after sexual assault should be provided with an emergency single dose of levonorgestrel and encouraged to present for follow-up evaluation.”

Pertinent Points:
- The use of a single 1.5-mg dose of levonorgestrel resulted in a pregnancy rate of 0.68% in women who reported to the emergency department after sexual assault.
- The use of a single dose of levonorgestrel instead of two 0.75-mg doses given 12 hours apart is a viable alternative method of emergency contraception.

References:

Reference

Choi DS, Kim M, Hwang KJ, et al. Effectiveness of emergency contraception in women after sexual assault.

Clin Exp Reprod Med.

2013;40:126-130.