While professional organizations affirm the safety and efficacy of medication abortion (MAB) at later first trimester gestational durations, US-based evidence remains limited. We propose a prospective cohort, open-label, non-inferiority study to evaluate the efficacy of MAB among 851 patients in four study groups with days gestation determined by ultrasonography: Comparison Group: 64 -70 days (n=267), Experimental Group 1: 78 – 84 days (n=267), Experimental Group 2: 85 – 91 days (n=267), and Exploratory Group: 92 days – 97 days (n=up to 50). We will use a 6% non-inferiority margin for the abortion success rate. We will assess safety, patient experience with side effects, patient acceptability, and patient experience with counseling materials, as secondary outcomes. Participants will take 200 mg mifepristone orally followed 24-48 hours later by 800 mcg misoprostol buccally every four hours + 2 doses (Comparison) or 3 doses (Experimental / Exploratory groups). Participants will return for a follow-up visit at 1-week to confirm abortion completion by ultrasonography. We will collect data through 1) medical chart/incident report abstraction from enrollment through 8-weeks post follow-up and 2) patient surveys: brief daily text contacts from enrollment to 1-week follow-up to collect data on medication use, symptoms, safety concerns, pregnancy status, and side effects, and surveys at the follow-up visit and remotely at day 28 to collect data on patient acceptability and perspectives on the counseling materials. This study will produce rigorous findings on the efficacy, safety, and acceptability at later gestational durations to expand evidence-based practice and access to MAB.