Etonogestrel implant effectiveness

Clinical question

How does the etonogestrel implant (Nexplanon) compare with other long-acting reversible contraception?

Bottom line

The etonogestrel implant is effective, with 0 to 0.34 pregnancies per 100 women per year. In 1 RCT, the implant had a higher discontinuation rate (27% vs 20%), more amenorrhea (29% vs 9%), and lower patient satisfaction (66% vs 80%) compared with a low-dose levonorgestrel intrauterine device (IUD).

Evidence

No statistical analysis unless mentioned.

• In 1 systematic review (51 studies),¹ only 1 RCT (766 women) compared a 68-mg etonogestrel implant with a 13.5-mg levonorgestrel IUD (Jaydess) over 12 months.²

  • - The RCT found the following: the number of pregnancies was 0 versus 3 (IUD); discontinuation was 27% versus 20% (IUD) (statistically different), mostly owing to adverse events (eg, increased bleeding 11% versus 3% [IUD]; acne 5% versus 3% [IUD]); patient satisfaction was 66% versus 80% (IUD) (statistically different); amenorrhea was 29% versus 9% (IUD); prolonged bleeding was 16% versus 5% (IUD); and normal bleeding pattern was 4% versus 31% (IUD).

  • - Limitations: The study was funded by the IUD manufacturer; IUDs available in Canada are higher in dose.

• An integrated analysis of 11 noncontrolled trials assessed a bioequivalent etonogestrel implant for 2 to 4 years (942 women, 18 to 40 years of age).³ Six women became pregnant, with conception presumed to be following implant extraction. The analysis found 0.34 pregnancies per 100 women per year in those with the implant.

  • - Adverse events leading to discontinuation: bleeding irregularities (11%), emotional lability (2%), weight gain (2%), headache (2%), acne (1%), and depression (1%). Insertion and removal complications were 1% and 2%, respectively.

  • - Limitations: The study was industry funded and not a systematic review.

• A noncomparative trial of the etonogestrel implant over 3 years (301 women, mean age 28) found similar efficacy and adverse events.⁴ The average weight gain was 1.4 kg at 36 months.

• Similar efficacy⁵ and insertion and removal complications⁶ were found in observational studies.

Context

• The etonogestrel implant is a subcutaneous, radiopaque, matchstick-sized flexible rod that lasts 3 years.^7,8 It costs roughly $310 versus $370 for hormonal IUDs, which last 5 years.⁷

• Training is required for insertion and removal.⁸

• Cases of pulmonary migration, infections, barium allergic reactions, and insertion-related neuropathies have been reported.⁹ No effect has been observed on bone mineral density.^10,11

Implementation

The most common reported adverse effect during etonogestrel implant insertion is “pins and needles/numbness” in the insertion limb, and it is more common among repeat users than new users (10 of 1000 repeat insertions vs 1.2 of 1000 new users).⁶ The implant can be inserted at any time, but backup contraception should be used for 7 days after insertion if not inserted between day 1 and 5 of the menstrual cycle.⁸ Efficacy and safety data are limited in women with obesity or irregular bleeding patterns as most studies excluded them.³