The hormonal implant, which is a small rod placed beneath the skin and the 52 mg hormonal intrauterine device (IUD) are two types of long-acting reversible contraception (LARC). The Food and Drug Administration (FDA) recommends replacement after three years for the implant and five years for the IUD because over time, their effectiveness decreases. This replacement incurs both discomfort and cost, depending on a one’s insurance coverage. A new study has found that these LARCs have effectiveness beyond the FDA guidelines; thus, significantly adding to their useful life. The findings were published in the March edition of the journal Obstetrics & Gynecology by researchers at Washington University in St. Louis School of Medicine, St. Louis, Missouri.
The study authors note that the increasing use of LARCs, specifically, IUDs and implants, has been shown to decrease the rate of unintended pregnancy because their effectiveness is not user-dependent. For example, birth control pills are less effective if a women forgets to take them even on occasion. Condoms and diaphragms also are user-dependent, Although rare, insertion of LARCs are associated with potential complications; thus, avoiding removal and reinsertion at the time of expiration may be of interest to the individual patient. In addition, the potential to further improve the cost-effectiveness by extending the life of these devices provides tremendous economic benefit to insurers and to society. Therefore, the goal of the study was to evaluate the effectiveness of the contraceptive implant and the 52-mg hormonal IUD in women using the method beyond the current FDA–approved duration of three years for the implant and five years for the hormonal IUD,
Women who were willing to continue using their implant or IUD beyond the FDA-approved duration were followed for contraceptive effectiveness. The unintended pregnancy rate per 100 women-years was calculated. Implant users were offered periodic venipuncture for analysis of serum etonogestrel levels.
The implant users (237 women) contributed 229.4 women-years of follow-up; 123 used the etonogestrel implant for 4 years and 34 used it for 5 years. No pregnancies occurred among this group, yielding a failure rate of 0. Among 263 IUD users, 197.7 women-years of follow-up were completed. One pregnancy occurred, yielding a failure rate of 0.51. Among implant users with serum etonogestrel results, the average and range of etonogestrel level at 3 years of use was 188.8 pg/mL (range: 63.8–802.6 pg/mL) and 177.0 pg/mL (range: 67.9–470.5 pg/mL) at 4 years of use. Etonogestrel levels did not differ by body mass index (BMI) at either time point, meaning that overweight women were as well protected as normal weight women.
The authors concluded that their preliminary findings indicate the contraceptive implant and 52-mg hormonal IUD continue to be highly effective for an additional year beyond the FDA-approved 3 and 5 years. Serum etonogestrel levels indicate the implant contains sufficient hormone for ovulation suppression at the end of both 3 and 4 years of use.