Perturbations in the normal vaginal microbiota, or community of microorganisms inhabiting the vaginal body niche, have long been known to affect the risk of transmission of HIV. Studies have shown altered vaginal microbiota with DMPA injection and preserved vaginal microbiota with the LNG IUD, but no studies have compared these methods head-to-head or used culture-independent sequencing methodology. The investigators propose a prospective pilot study to evaluate the impact of different long-acting progestin contraceptive formulations on the vaginal microbiome. Specifically, the investigators aim to identify and compare metagenomics profiles associated with DMPA, LNG IUD, and ESI contraceptive use by community analysis of vaginal swab samples from women collected longitudinally after contraceptive method initiation. The investigators hypothesize that DMPA will increase community diversity in the vaginal microbiota, whereas the LNG IUD and ESI will not affect the balance of microorganisms in the vagina. Women who are planning to initiate DMPA, LNG IUD, and ESI contraception as well as controls not seeking contraception will be recruited for the study from Boston Medical Center (BMC), a tertiary care center with a racially and socioeconomically diverse patient population. Women will have longitudinal follow-up with self-sampling of the vagina for sexually transmitted infection testing and metagenomics analysis at method initiation, 2-3 months, and 6 months. Establishing the safest long-acting progestin contraceptive alternative will promote effective contraception use and lower rates of HIV acquisition worldwide.