There is a demand for estrogen-free contraception in order to reduce the risk of venous thromboembolism (VTE), particularly of obese women. A new long acting formulation of Levonorgestrel Butanoate (LB), delivered by injection, has been developed. Levonorgestrel (LNG) has a long history of clinical use in a variety of contraceptives (pills, intrauterine devices, and implants) and its efficacy and safety are well recognized.