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Longer term use of IUD or implant found effective in prospective study

Both the etonogestrel implant and the 52-mg levonorgestrel IUD are safe and effective when used beyond the current FDA-approved usage duration, according to a recently published study.

“The etonogestrel subdermal implant and the 52-mg levonorgestrel IUD are among the most effective forms of reversible contraception available with a failure rate of less than 1% over the 3-year and 5-year FDA-approved durations,” Colleen McNicholas, DO, MSCI, of the division of clinical research at Washington University, and colleagues wrote.

Researchers evaluated 500 women already using either a subdermal etonogestral implant (n = 237) or a 52-mg levonorgestral intrauterine device (IUD) (n = 263) between January 2012 and November 2014. Participants agreed to continue contraceptive device usage beyond the FDA-approved length of 3 years for implants and 5 years for IUD.

The researchers assessed participant pregnancy rate per 100-women-years, serum etonogestrel levels and compared etonogestrel levels for different BMIs.

Researchers followed up with implant users for 229.4 women-years; 123 women continued implant use for an extra 1 year, and 34 for an added 2 years. Zero pregnancies were reported, resulting in a failure rate of 0 (one sided 97.5% CI, 0-1.61) per 100 women-years.

The IUD users had an average of 197.7 women-years of follow-up; 108 women continued use for at least one additional year. One pregnancy was reported, resulting in a failure rate of 0.51 (95% CI, 0.01-2.82) per 100 women years.

The median and range serum etonogestrel levels at 3 years of implant or IUD use was 188.8 pg/mL (63.8-802.6 pg/mL) and 177 pg/mL (67.9-470.5 pg/mL) at 4 years of use.

There was no significant difference, at any time, in etonogestrel levels among BMI groups.

“With many women experiencing access barriers [to long-acting contraceptives], knowledge regarding the extended use of these methods beyond the current U.S. FDA-approved duration would allow women to continue to confidently use their current method in the event they could not access or afford a new device,” McNicholas and colleagues wrote. – by Casey Hower

Disclosure: McNicholas reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.