progestogen only implant (contraceptive) and obesity

Last edited 03/2020 and last reviewed 05/2021

Progestogen-only implants

• the etonogestrel (ENG) implant is a highly effective method of contraception and available evidence suggests that its effectiveness is not affected by body weight or BMI. The licensed duration of ENG implant use of 3 years applies to women of all weight categories
  
  
• the available evidence suggests that the ENG implant is a safe contraceptive option for women who are overweight and women with obesity

Weight gain with implants

• in the general population of all implant users, there is no evidence of a causal association between implant use and weight gain. There is no specific evidence relating to weight gain with IMP use by women who are overweight or women with obesity

The Summary of Product Characteristics (SPC) for the ENG progestogen-only implant advises that "the clinical experience in heavier women in the third year of use is limited". It therefore states that "it cannot be excluded that the contraceptive effect may be lower than for women of normal weight". It advises that health professionals may therefore consider earlier replacement of the implant in ‘heavier’ women. The SPC does not specify a definition of heavier weight or after what duration of use replacement may need to be considered. The FSRH advises that there is no direct evidence to support a need for earlier implant replacement, and recent data assessing continued use in women with raised BMI beyond 3 years are very reassuring. Therefore the FSRH guidance is that the ENG implant can be considered to providevery effective contraception for 3 years for women in all weight/BMI categories

The single-rod etonogestrel (ENG) implant (Nexplanon) is the only implant currently available in the UK (1)

Reference:

• FSRH (April 2019). Overweight, Obesity & Contraception