Importance: Having a child with a major birth defect can be a life-changing and stressful event that may be associated with higher cardiovascular disease (CVD) risk, yet the long-term burden of CVD for the child's mother is unknown. Objective: To assess whether mothers of an infant born with a major congenital anomaly are at higher risk of CVD compared with a comparison cohort. Design, Setting, and Participants: A population-based cohort study using individual-level linked registry data in Denmark included 42 943 women who gave birth to an infant with a major congenital anomaly between January 1, 1979, and December 31, 2013; and follow-up was conducted until 2015. A comparison group, comprising 428 401 randomly selected women, was 10:1 matched to each affected mother by maternal age, parity, and her infant's year of birth. Data analyses were performed between November 1, 2017, and February 28, 2018. Exposures: Live birth of an infant with a major congenital anomaly. Main Outcomes and Measures: The primary outcome was a CVD composite outcome of acute myocardial infarction, coronary revascularization, or stroke. Secondary outcomes included individual components of the CVD composite and other cardiovascular outcomes, including unstable angina, congestive heart failure, atrial fibrillation, peripheral artery disease, ischemic heart disease, and aortic aneurysm. Cox proportional hazards regression analyses generated hazard ratios (HRs), adjusted for maternal demographic, socioeconomic, and chronic health indicators. Results: Median maternal age at baseline was 28.8 years (interquartile range, 25.3-32.5 years). After a median follow-up of 19.5 years (interquartile range, 9.9-27.6 years), 914 women whose infant had a major congenital anomaly experienced a CVD event (1.21 per 1000 person-years; 95% CI, 1.13-1.28 per 1000 person-years) vs 7516 women in the comparison group (0.99 per 1000 person-years; 95% CI, 0.97-1.01 per 1000 person-years), corresponding to an unadjusted HR of 1.23 (95% CI, 1.15-1.32), and an adjusted HR (aHR) of 1.15 (95% CI, 1.07-1.23). Women who gave birth to an infant with multiorgan anomalies had an even higher aHR (1.37; 95% CI, 1.08-1.72). Mothers of infants with a major anomaly also had an increased aHR of the individual components of the composite outcome and the other cardiovascular outcomes. Conclusions and Relevance: Women whose child had a major congenital anomaly experienced a 15% to 37% higher risk of premature cardiovascular disease. These women may benefit from targeted interventions aimed at improving their cardiovascular health.