Endometrial Biopsy in Progestin Contraceptive Users

The purpose of the study is to learn more about menstrual changes in progestin contraception users. The investigators are hoping to find out what changes in the endometrium lead to different bleeding patterns during the first year of progestin contraception use. Participants will choose to receive the contraceptive implant (Etonogestrel implant also called Nexplanon) or the contraceptive injectable (Depo-medroxyprogesterone acetate (DMPA) also called Depo-Provera) for up to 12 months. They will be asked to have 4 endometrial biopsies over the course of the study, as well as blood draws, physical exams, and pregnancy tests. Participants will also use a daily text message or email diary to report bleeding patterns. This study's plan is to comprehensively phenotype bleeding patterns and profile the entire endometrium using single-cell RNA seq data (sCRNAseq).