Effectiveness of contraceptives in obesity

Combined hormonal contraception, progestogen-only pills, levonorgestrel-releasing IUDs (LNG-IUDs) and depot medroxyprogesterone do not require dose adjustment in individuals with obesity.

Early replacement of the etonogestrel implant (after the second year of use) may be considered on a case-by-case basis if regular cycles resume. However, there is no evidence to suggest an increase in pregnancies in the third year of use in individuals with a high BMI.

The effectiveness of oral emergency contraception may be affected by increased weight:

• Levonorgestrel may be less effective if BMI is more than 26 kg/m² or weight is more than 70 kg; consider a copper IUD or a double dose of levonorgestrel.
• Ulipristal may be less effective if the BMI is more than 30 kg/m² or weight is more than 85 kg; consider a copper IUD (a double dose of ulipristal is not recommended).