Pharmacological Evaluation of Hormonal Contraceptive Treatments in Obese Women Before and After Bariatric Surgery

Open, multi-center pharmacological study of residual concentrations of three different oral contraceptives in 3 groups of obese women in each group of surgery, and 1 group of healthy volunteers. The concentrations will be assessed before, 6 and 12 months after bariatric surgery restrictive (sleeve gastrectomy) or malabsorptive (gastric by pass).

Contraception is an important issue in women with obesity. There are actually few data answering the questions of the efficacy of oral contraceptive in obese women, as this condition could be a risk factor for failure of hormonal contraception, due to the changes in drug metabolism and a larger volume of distribution in obesity. Bariatric surgery is the most efficient therapeutic for weight loss in severe and morbid obesity. In 2011, more than 31 000 bariatric procedures have been performed in France with sleeve gastrectomy and Roux-en-Y gastric bypass (RYGB) representing the two most frequent procedures. Women represent 80 % of surgical patients and most of them are in childbearing age (mean age of 39 years). Obese women who receive surgical treatment for obesity are advised not to conceive for the following 12 to 18 months, both to ensure optimal weight loss and a stable weight during pregnancy, and also to begin pregnancy with optimal nutritional and vitamin status. There are no data on the changes in oral contraceptives concentrations before and after bariatric surgery, as malabsorption and anatomic digestive modifications following surgery may theoretically affect bioavailability.

Primary Objective :

The difference between Css before bariatric surgery and 6 months after the surgery in obese women regardless of the oral contraceptives used. Three different oral contraceptives are employed (two combined oral contraceptive containing ethinyl E2 and levonorgestrel and a progestin contraceptive desogestrel).

Secondary Objectives :