Etonorgestrel concentrations in morbidly obese women following Roux-en-Y gastric bypass surgery: three case reports

Contraception. 2011 Dec;84(6):649-51. doi: 10.1016/j.contraception.2011.03.015. Epub 2011 May 8.


Background: Pregnancy should be avoided for 12 to 18 months after Roux-en-Y gastric bypass (RYGB) surgery. The etonorgestrel (ENG)-releasing implant (Implanon®) may represent a safe and effective contraceptive method in morbidly obese women who are candidates for bariatric surgery. In addition, the subcutaneous delivery of steroid is unaffected by malabsorptive surgery.

Methods: Three cases of young women with ENG-releasing implant are reported. The device was inserted 1-2 months prior to RYGB.

Results: Their initial weights were 130 to 176 kg, and the mean weight loss was 33.6 kg at 6 months. The concomitant serum ENG concentrations decreased currently with weight loss but remained above the minimum concentration required for effective contraceptive effect of the implant for at least 6 months following RYGB (average, 170 pg/mL). The concentrations observed before weight loss were lower than in normal-weight women, but decreases in ENG concentrations following implant insertion were similar.

Conclusion: These unique data in morbidly obese women highlight the need for further pharmacokinetic studies of contraceptive agents in obese women during weight loss.

Publication types

  • Case Reports

MeSH terms

  • Adsorption
  • Adult
  • Body Mass Index
  • Contraceptive Agents, Female / administration & dosage
  • Contraceptive Agents, Female / blood*
  • Contraceptive Agents, Female / pharmacokinetics
  • Desogestrel / administration & dosage
  • Desogestrel / blood*
  • Desogestrel / pharmacokinetics
  • Drug Implants
  • Female
  • Gastric Bypass*
  • Humans
  • Obesity, Morbid / blood*
  • Obesity, Morbid / surgery*
  • Weight Loss
  • Young Adult


  • Contraceptive Agents, Female
  • Drug Implants
  • etonogestrel
  • Desogestrel