Long-acting contraceptives work beyond FDA-approved duration

By Megan Brooks

NEW YORK (Reuters Health) - The etonogestrel contraceptive implants and the 52-mg levonorgestrel intrauterine device (IUD) provide highly effective birth control a year longer than the U.S. Food and Drug Administration (FDA)-approved duration of use, preliminary findings from an ongoing study suggest.

Showing the methods are effective for longer boosts their "cost-effectiveness (and) also helps women delay or avoid the visits, costs, and procedures related to removal and reinsertion," first author Dr. Colleen McNicholas, assistant professor of obstetrics and gynecology at Washington University School of Medicine in St. Louis, told Reuters Health by email.

The findings support other studies conducted by the World Health Organization and European researchers that have shown that IUDs and implants may be effective for longer periods of time, the researchers say.

The etonogestrel implants Implanon and Nexplanon are approved for three years duration and the 52-mg LNG IUD Mirena is approved for five years.

In an ongoing study, Dr. McNicholas and colleagues are looking at whether these long-acting contraceptives provide effective birth control for up to three years past their recommended length of use.

In a preliminary analysis published online February 4 in Obstetrics & Gynecology, they report on 237 women who have continued with their implant for a median of 12.5 months past the recommended use date and 263 women who have continued their IUD for a median of 11.7 months beyond the recommended use date.

The implant users have contributed 229.4 women-years of follow-up and no pregnancies have occurred in these women, for a failure rate of 0 per 100 women-years, the researchers report.

The 263 IUD users have completed 197.7 women-years of follow-up and only one pregnancy was confirmed, a failure rate of 0.51 per 100 women-years, which is on par with the failure rate of IUDs used within the recommended five-year window, they point out.

They say etonogestrel levels did not vary by BMI, and the median level remains above the threshold for ovulation suppression.

"Take-home message: Both the 52-mg LNG IUD and the contraceptive implant are effective in the year beyond their FDA-approved duration. That means clinicians should feel comfortable that the LNG-IUD can be used safely for 6 years and the implant for 4 years," Dr. McNicholas told Reuters Health.

"The longer a contraceptive method is effective, the bigger the impact it can have," senior author Dr. Jeffrey Peipert, professor of obstetrics and gynecology at Washington University, said in a statement. "In the long term, this work has the potential to change how we provide contraceptive methods around the world and can enable women to control their reproductive health and family size."

The study has no commercial funding. Dr. Peipert has disclosed relationships with Bayer, Teva, Merck, and Watson/Actavis.

SOURCE: http://bit.ly/1IpN8vP

Obstet Gynecol 2015.

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