Hormonal intrauterine devices (IUDs) and contraceptive implants remain effective one year beyond their approved duration of use, preliminary research from the Washington University School of Medicine has found. The study’s findings are published in Obstetrics & Gynecology.

Contraceptive implants are currently approved by the Food and Drug Administration (FDA) for three years, and hormonal IUDs are approved for five years. Researchers are studying whether these long-acting birth control methods are effective for up to three years beyond the recommended length of use.

RELATED: Contraceptive Choice May Affect RA Development in Women

Mirena (levnorgestrel; Bayer), a hormonal IUD, and Implanon (etnogestrel; Merck) and Nexplanon (etonogestrel, barium sulfate; Merck), two contraceptive implants, were evaluated in this study of 800 women aged 18–45 years old. The initial analysis included 237 women who used implants and 263 women who used hormonal IUDs. The participants’ contraceptives had to be within six months of expiration when they enrolled.

Overall, the researchers reported no pregnancies among women in the in the implant group, and one pregnancy in the IUD group. The failure rate was similar to that of IUDs when used within the approved 5-year use. The study will continue to follow-up on the participants to determine if contraceptive IUDs and implants are effective up to 3 years beyond the approved duration of use.

For more information visit WUSTL.edu.