Association between adverse birth outcomes and long-term risk of premature cardiovascular disease and mortality in a contemporary population-based cohort of 502,383 pregnant women

BACKGROUND: Relatively few studies have examined the association between the entire spectrum of adverse birth outcomes [stillbirth, preterm birth (PTB), term births that are low birth weight (LBW) or high birth weight (HBW)] and long-term risk of CVD in the mother. Our objective was to examine the association between birth outcomes and risk of premature CVD or death in a contemporary cohort of pregnant women. METHODS: We conducted a retrospective population-based cohort study of women in Alberta, Canada, between 01/01/2005 and 01/01/2023. The primary endpoint was a composite of CVD-related hospitalization, CVD-related emergency department visit, or death. Cox proportional hazard modelling was used to examine the independent association between birth outcomes and the risk of CVD or death in the mother, after accounting for other socio-demographic, clinical and pregnancy-related complications. RESULTS: Among 502,383 mothers, 0.51% had stillbirth, 7.11% had PTB, 86.11% had normal birth weight (NBW), 2.11% had LBW, and 4.15% had HBW. During a median follow-up of 3612 days (∼10 years), compared the NBW group, the adjusted hazard ratio (aHR) and 95% confidence interval (CI) for maternal CVD or death associated with stillbirth was 1.63 (1.33, 1.99); 1.45 (1.36, 1.55) for PTB; 1.22 (1.06, 1.41) for LBW, and 1.13 (1.03, 1.23) for HBW. In addition to birth outcomes, pre-existing diabetes (aHR: 1.61, 95% CI: 1.47, 1.76), gestational hypertension (aHR: 1.47, 95% CI: 1.38, 1.57), and pre-existing hypertension (aHR: 3.28, 95% CI: 2.66, 4.04) carried a higher risk for premature CVD and death in the mother. CONCLUSIONS: Adverse birth outcomes of stillbirth and preterm birth, and to a lesser degree term births that result in LBW or HBW, are markers of increased risk of premature CVD and death in the mother. Coordinated effort between obstetricians, family physicians, and cardiologists are needed to design and implement effective risk reduction programs tailored for these high-risk women.