d members across 21 medical centers and 250 clinics. The study included women aged 18–45 years with continuous health plan membership for at least 2 years in the pre-ACA (2007–2012) and post-ACA (2013–2018) periods. We analyzed out-of-pocket (OOP) costs for contraception, including oral contraceptives and long-acting reversible contraception (LARC), before and after the ACA’s implementation. We then examined how the elimination of OOP costs affected contraception use, pregnancy rates, and abortion rates. RESULTS: The study identified 1,523,962 women of childbearing age. In 2013, cost sharing for contraception sharply declined, with average annual OOP costs dropping from $88–94 pre-ACA to nearly zero post-ACA. Contraceptive use increased overall, rising from 30.2% pre-ACA to 31.9% by the study’s end, with a notable rise in LARC use. In interrupted time-series analyses, contraception use continued to increase post-ACA, new pregnancy rates declined at a faster rate than pre-ACA, and abort