Pregnancy Data Among LNG- and ENG-Releasing Subdermal Implant Users Through 5 Years of Use From Ali et al., 201618

LNG-Releasing ImplantENG-Releasing Implant
Years 1–3aYear 4aYear 5Years 1–5 (Cumulative)Years 1–3aYear 4aYear 5Years 1–5 (Cumulative)
No. of women997470330995311204
Woman-months of observation286706,2544,62930,325287864,6062,45422,044
No. of pregnancies3b0033b003
Cumulative pregnancy rates per 100 woman-yearsc (95% CI)0.4 (0.1–1.4)0.8 (0.2, 2.3)0.4 (0.1–1.4)0.6 (0.2, 1.8)
  • Abbreviations: CI, confidence interval; ENG, etonogestrel; LNG, levonorgestrel.

  • a Cut-off for 3 years was at 38 months post-insertion while year-4 data started at 36 months post-insertion, resulting in a 2-month overlap in data. Woman-months of observation between these 2 time periods, however, is not additive.

  • b Pregnancy data from the first 3 years reported in Bahamondes et al., 2015.22

  • c Kaplain-Meier rates.