The Heart Outcomes for Pregnancy Expectations Study - The US not only has the highest rate of maternal mortality in the developed world but is the only country in which this rate is rising. While affecting only 1-4% of pregnancies, cardiovascular disease (CVD) accounts for ~30% of maternal deaths and yet there no is evidence about how best to stratify risk or deliver care to this high-risk population. While cardio-obstetrics (COB) clinics have emerged, with encouragement and support from the AHA and ACOG, these have been implemented very heterogeneously. In collaboration with a large network of COB clinics, we have identified 5 structural components of care that have been variably deployed, and for which further evidence is needed to define whether any of these independently improves outcomes. Along with 33 partner sites, we propose the first-ever, US-based, prospective evaluation of 1000 consecutive pregnant women with CVD to identify clinical, patient-reported, and structural characteristics of care associated with adverse pregnancy outcomes (APO), maternal adverse cardiac outcomes (MACE), neonatal adverse clinical events (NACE) and quality of life (QoL). Our study will address the exceedingly high prevalence of adverse outcomes pregnant women with CVD by: 1) Identifying patient characteristics at the time of prenatal care initiation and throughout pregnancy associated with APOs, NACE and MACE; and 2) By adjusting for these factors, define the independent association of alternative structures of care, with outcomes, so that more effective COB practices can be developed and disseminated to reduce maternal mortality and morbidity and improve neonatal outcomes. We will prospectively collect detailed patient-level variables, and the first ever serial assessment of quality-of-life data, from initial COB clinic presentation throughout pregnancy, delivery, and 1 year after delivery. This will be the first national, multisite, prospective study of pregnant women with CVD ever conducted in the US and to address our country's rising maternal morbidity and mortality. Moreover, given the lack of evidence-based observational insight into what practices improve outcomes in which patients, this work will be foundational for future clinical trials. To accelerate the translation of our findings to clinical practice, we have actively engaged dissemination partners to join us in the design, analysis, and interpretation of our findings to accelerate their efforts to improve maternal care.