The levonorgestrel 52-mg intrauterine device (IUD) was found to be noninferior to copper IUD when used as emergency contraception in a randomized trial involving close to 650 women who presented within five days of having unprotected sex.
In a modified, intention-to-treat and per-protocol analyses, the pregnancy rate among the hormonal IUD group was 0.3% compared to 0% in the copper IUD group.
Findings from the multicenter, randomized trial support “provision of quick-start contraception with the levonorgestrel 52-mg IUD after recent unprotected sexual intercourse and a negative pregnancy test,” wrote researcher David K. Turok, MD, of the University of Utah Health Sciences Center, Salt Lake City, and colleagues in The New England Journal of Medicine.
Oral levonorgestrel and oral ulipristal acetate are the only emergency contraception approved by the U.S. Food and Drug Administration, but copper IUDs have been shown to be highly effective for emergency contraception, with a pregnancy prevention failure rate of less than 0.1% in a systematic review of decades of use.
Earlier preliminary research by Turok and colleagues showed a user preference for the hormonal IUD with commitment oral levonorgestrel compared to copper IUD among women seeking emergency contraception.
Despite the fact that a high percentage of women in the study had a high risk for emergency contraception failure (40% reported multiple episodes of unprotected sexual intercourse and 61% had BMIs of 25 or higher) no pregnancies occurred among the 121 women treated with the levonorgestrel regimen.
“This, along with evidence of the effectiveness of inert IUDs, has suggested that the levonorgestrel IUD could be effective for emergency contraception,” Turok et al. wrote. “Moreover, laboratory data support the potential for levonorgestrel to directly interfere with sperm transport, sperm capacitation, the acrosome reaction, and oviduct transport.”
Their newly published noninferiority clinical trial included women seeking emergency contraception treated with either a levonorgestrel IUD or a copper IUD at 1 of 6 family planning clinics in Utah. The women were not aware of which IUD they were getting, and all reported at least 1 episode of unprotected intercourse within 5 days of presentation.
The primary study outcome was positive urine pregnancy test within 1 month of IUD insertion or survey and health record data to determine pregnancy status, and the prespecified noninferiority margin was 2.5%.
A total of 317 and 321 women, respectively, received the levonorgestrel IUD or copper IUD and provided 1-month outcome data, with results of a 1-month urine pregnancy test available for 290 in the levonorgestrel group and 200 in the copper IUD group.
Among the main study findings:
- In the modified intention-to-treat and per-protocol analyses, pregnancy rates were 1 in 317 (0.3%, 95% CI, 00.1-1.7) in the levonorgestrel group and 0 in 321 (0%, 95% CI, 0-1.1) in the copper IUD group.
- Results from both analyses were consistent with the noninferiority of the levonorgestrel IUD to the copper IUD.
- Adverse events involving seeking medical care during the first month after insertion occurred in 5.2% and 4.9%, respectively, of the levonorgestrel and copper IUD groups.
In addition to a significant percentage of participants reporting multiple recent incidences of unprotected sex, some also reported unprotected intercourse occurring 6 to 14 days before IUD placement.
Turok and colleagues previously reported on a pooled cohort of 134 women who had a copper IUD placed 6 to 14 days after having unprotected intercourse, with no pregnancies occurring in the group.
A potential limitation of the newly reported analysis cited by the researchers was overestimation of the number of participants who would provide 1-month follow-up data. Selection bias was also possible, they wrote, since only 7% of clinic patients seeking emergency contraception were enrolled in the trial. Not wanting an IUD was frequently cited by women who declined to participate.
“Because clinics serving as trial sites are known to provide low-cost oral emergency contraception rapidly, some women may not have wanted to spend the additional time at the clinic required for trial enrollment and IUD placement,” they wrote. “The nature of the trial sites may also limit generalizability, as did our exclusion of persons outside the 19-to-35-year age range and those with irregular menstrual cycles.”
Implantation of a hormonal IUD was found to be noninferior to copper IUD when used as emergency contraception among women who presented within five days of having unprotected sex.
In modified, intention-to-treat and per-protocol analyses, the pregnancy rate among the hormonal IUD group was 0.3% compared to 0% in the copper IUD group.
Salynn Boyles, Contributing Writer, BreakingMED™
Turok disclosed grant support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development and a consultant agreement with Sebala Pharmaceuticals Inc. Additionally, he serves as director of surgical services for Planned Parenthood of Utah.
Cat ID: 191
Topic ID: 83,191,730,191,40,41,192,925