Effectiveness and safety of extending intrauterine device duration: a systematic review

Abstract

To systematically review the literature to determine if extended use of intrauterine devices, including the copper or levonorgestrel intrauterine device, beyond approved durations is effective and safe for preventing pregnancy. We searched PubMed, Embase, Cumulative Index to Nursing and Allied Health Literature, and Global Index Medicus from inception through June 2019. We considered primary studies of women using the T380A copper or currently available levonorgestrel intrauterine devices past their approved duration (extended use). The primary outcome was pregnancy. Safety outcomes included adverse events and side effects that led to discontinuation. We abstracted study data into evidence tables and assessed study quality as related to the risk of bias, precision, and external validity. For each intrauterine device type, we calculated a pooled pregnancy rate during the first 2 years of extended use using the Poisson inverse variance method. Of 4068 studies identified by our search, 4 good-to-poor-quality studies of the 52 mg levonorgestrel intrauterine device (approved for 5 years), with a total of 2098 women starting extended use, and 2 good-to-fair-quality studies of the T380A copper intrauterine device (approved for 10 years), with 245 women starting extended use, met inclusion criteria. For the levonorgestrel intrauterine device, the pooled pregnancy rate was 0.02 per 100 person-years (95% confidence interval, 0.00-0.45) in year 6, 0.03 per 100 person-years (95% confidence interval, 0.00-0.71) in year 7, and 0.02 per 100 person-years (95% confidence interval, 0.00-0.29) in years 6 and 7 combined. During this same time, annual rates of adverse events or discontinuation owing to side effects ranged from 0 to 3.7 per 100 participants. For the copper intrauterine device, the pooled pregnancy rate for years 11 and 12 was 0.0 per 100 person-years (95% confidence interval, 0.0-0.8), and annual rates of adverse events and discontinuation owing to side effects during extended use ranged from 0 to 4.6 per 100 participants. The available evidence suggests that rates of pregnancy, adverse events, and discontinuation owing to side effects during the first 2 years of extended use of the 52 mg levonorgestrel intrauterine device and the T380A copper intrauterine device are low and comparable to rates during approved duration of use. Data were limited in quantity and quality, and may not be generalizable to all intrauterine device users.