Their popularity is on the rise, and now their duration might be too; researchers think that intrauterine devices (IUDs) and hormonal implants may work for one year longer than their intended length of use.
A new study, published in the journal Obstetrics & Gynecology, looked at 263 woman using the IUD Mirena and 237 using the implants Implanon and Nexplanon. (FYI: An IUD is inserted into the uterus, while an implant is placed in the upper arm.) Mirena is FDA-approved for five years of use, while the implants last for three. The stipulation for participation? The women's contraceptives had to be within six months of expiring when they enrolled, and the participants were told that there would be a risk of conceiving.
A year went by in which none of the women used any other form of birth control — just their newly-expired contraceptives. None of the women using implants got pregnant, and only one using an IUD did.
"This research is important because extended use of these devices will reduce cost to both the individual and insurer and improve convenience for women, who can delay removal and re-insertion,” says study author Colleen McNicholas, assistant professor of obstetrics and gynecology at Washington University.
The next step? Researchers will expand the study and see how reliable these contraceptives are three years after their current expiration dates.