TABLE. Pregnancy Rates in Studies of Contraceptive Implants and the Antiretroviral Efavirenz
Implant Type and StudyMethodologyNo. of WomenNo. of PregnanciesPregnancy Rate (95% CI)Period of Use
LNG
 Patel11Retrospective electronic database191a67.1 (1.5, 12.6)Unknown
 Perry12Retrospective chart review1211510a16.4 months
 Scarsi13Prospective clinical2031548 weeks
ENG
 Patel11Retrospective electronic database641a155.5 (2.5, 8.4)Unknown
 Kreitchmann14Prospective clinical25b003 years
Unknown
 Pyra15Secondary analysis of prospective study9a16Unknown

  • Abbreviations: CI, confidence interval; EFV, efavirenz; ENG, etonogestrel; LNG, levonorgestrel.

  • ↵a​ Estimated from data in publication.

  • ↵b​ Believed to be predominantly EFV users.