Comparison Between Levonorgestrel and Etonogestrel Implants, the Two Silicone-Based Long-Acting Reversible Subdermal Contraceptives

Abstract

Abul Kalam Lutful Kabir and Emdad Hossain

Levonorgestrel (LNG) and etonogestrel (ENG) subdermal implants symbolize the most widely used long-acting reversible contraceptives (LARCs) among modern family planning methods and offer 3-5 years of protection against unintended pregnancies (UPs), by providing effective and user-friendly contraception. In this review, we have performed a comparative analysis of both types of implants with respect to their historical evolution, chemical and pharmaceutical differences, clinical performance, such as safety, efficacy, and acceptability, side effect profiles, global accessibility, cost-effectiveness, and overall satisfaction and implications for users’ health, independence, and socioeconomic contribution. LNG implants (e.g., Jadelle, Sino-implant II) and ENG implants (Implanon, Nexplanon) show more than 99% of contraceptive efficacy for the intended duration with serum progestogen levels enduring above the threshold to suppress ovulation, needed for contraception. LNG implants offer 3-5 years of contraception, whereas ENG implants, although labeled for 3 years, demonstrate evidence of 5 years of pregnancy protection. Common side effects include weight gain, irregular menstruation, and frequent bleeding, with ENG usually accompanied by easier insertion and removal and a low rate of early discontinuation. LNG implants are more cost-effective and generally subsidized in low-income countries, whereas ENG implants prevail more in high-income regions due to their higher cost. These two reversible contraceptive implants boost user compliance, diminish unintentional gravidity, and have a positive influence on the women’s lifestyle, freedom, and reproductive health. Therefore, both implants are highly effective, safe, and acceptable LARCs, with discrete benefits in length of duration, availability, and acceptability, and their wider range of contraception, mostly in low-resource regions, can significantly decrease the problem of UPs during women’s empowerment and socioeconomic promotion.

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