Implanon effectiveness after 3 years: what the research shows

Implanon NXT is the etonogestrel contraceptive implant. The product label says to replace it at 3 years. Some studies followed users for longer and found very low pregnancy rates in years four and five. That extended use is off-label in many countries, so decisions should be made with a clinician who knows your situation.

What the evidence says

A WHO-led cohort reported no pregnancies among users who kept the etonogestrel implant into years four and five. You can read the study here: Ali et al., Contraception 2016. The authors concluded effectiveness remained very high during those extra years, noting the sample size was modest.

Professional guidance reflects this evidence but varies by region. The American College of Obstetricians and Gynecologists notes effectiveness for at least 4 years and reports no pregnancies in one study through 5 years. UK guidance (FSRH) recognises data with no pregnancies in extended years and emphasises counselling and local policy. In Australia, the label for Implanon NXT remains 3 years.

What this means in practice

  • If the implant is at or past 3 years and pregnancy would be unacceptable, replacement on time is the most conservative option.
  • If access is delayed, discuss temporary backup and whether short-term extension is reasonable for you.
  • Weight alone is not a reason for early replacement according to UK guidance, though data in very high BMI are limited.

Estimate your risk

Use the Contraceptive Risk Calculator to see a per-act estimate using “contraceptive implant (the rod)” and your age.

How the implant works, briefly

The rod releases etonogestrel. It mainly prevents ovulation and also thickens cervical mucus. These effects decline slowly over time, which is why researchers have studied longer durations.

Methodology & sources

This article is general information, not medical advice.

For broader context on methods and effectiveness, see Contraceptives & fertility.