The Effect of Body Mass Index on Etonogestrel Hormone Levels in Women Using the Single-rod Contraceptive Implant

Two-thirds of young women in the United States are overweight or obese. This excess weight may affect how their body metabolizes drugs such as different birth control methods. There is a not a lot of research about how excess weight could affect the hormone levels of the contraceptive implant. Methods like the implant contain only progesterone, which is a hormone that does not increase a woman's risk of blood clot. These methods would be preferred for overweight and obese women because excess weight also increases a woman's risk of blood clot. The investigators propose a study comparing blood hormone levels of women using the implant for at least twelve months and in all weight categories. The investigators hope to show that all women, regardless of weight, will have hormone levels high enough to prevent pregnancy.