Research Studies

a. Good general health b. Age between 18 and 40 years at the time of etonogestrel implant insertion c. BMI less than or equal to 28kg/m2 d. Intact uterus with at least one ovary e. Regular menstrual cycles that occur every 21-35 days: i. If patient is postpartum or post-second trimester abortion, she must have 3 menses (2 cycles) prior to enrollment ii. If patient had a first trimester abortion or pregnancy loss, she must have one spontaneous menses prior to enrollment f. Desires insertion of an etonogestrel contraceptive implant for contraception g. Have a negative urine pregnancy test at the etonogestrel implant insertion visit and no unprotected penetrative penile-vaginal intercourse for the previous 10 days. h. Must be consistently using a barrier method or other non-hormonal birth control method throughout the study, or is otherwise not at risk for pregnancy i. Patients must be ovulatory as confirmed by a documented screening progesterone (P4) level >= 3ng/ml by local laboratory. j. Willing to abstain from medications and supplements known to induce/inhibit CYP3A4 during the study k. In the opinion of the investigator, patient is willing and able to comply with the protocol requirements. l. Lives within the study site catchment area or within a reasonable distance from the site.

To enroll into the clinical trial, potential patients must not: a. Have a known hypersensitivity or contraindications to etonogestrel. b. Planned significant weight loss during the study related to bariatric surgery, dieting, or other causes. c. Currently taking any known CYP3A4 inducers/inhibitors d. Medical conditions that affect liver function (e.g., hepatitis, cirrhosis; assessed via participant self-report) e. Known or suspected current alcohol dependence syndrome or any illicit drug use that may affect the metabolism of the etonogestrel. f. Undiagnosed abnormal uterine/genital bleeding. g. Uncontrolled thyroid disorder. h. Use of long-acting injectable hormonal contraceptive within the past 9 months prior to enrollment unless the patient has had at least one spontaneous menstrual cycle (at least two menses) since the last injection. i. Recent use of hormonal oral, patch, intravaginal, or intrauterine contraception unless that patient has had at least one spontaneous menstrual cycle (at least two menses) since discontinuation. j. Currently breastfeeding or are within 30 days of discontinuing breastfeeding unless the patient has already had a menses following discontinuation. k. Planning on undergoing major surgery during study participation. l. Planning pregnancy during their anticipated months of study participation.