Pregnancy related cardiovascular disease – time trends and risk factors

Background Maternal cardiovascular disease (CVD) represents the leading cause of non-obstetric maternal mortality, affected women face an elevated risk of future cardiovascular events.(1, 2) To inform prevention strategies, it is important to estimate incidence of CVD and impact of risk factors . Purpose To assess temporal trends in pregnancy-related CVD incidence and prevalence of risk factors and quantify their impact using population attributable fractions (PAFs). Methods Using Danish nationwide registries, we identified all pregnancies from 1 January 2004 to 31 December 2023 among women without prior CVD and followed them from pregnancy onset until 1 year postpartum, CVD, death, or end of follow-up. CVD was defined by ICD-10 codes for heart failure and cardiomyopathy (HF), coronary artery disease (CAD), and ischemic stroke (ICS). Incidence was calculated per 10,000 pregnancies and stratified by calendar year. PAFs were estimated for major risk factors including maternal age ≥35 years, obesity, preeclampsia, diabetes, gestational diabetes, smoking, dyslipidaemia, and thrombophilia. Corresponding confidence intervals (CI) were derived using bootstrap resampling. Results In total 1,195,279 pregnancies were identified, with a total of 828 women experiencing CVD (no. of CAD: 274, HF: 361, ICS, 214). Women with CVD had a higher mean age (32.3 vs. 30.4, p<0.001), were more frequently smokers (19.5%, vs. 11.4%, p<0.001), more often had preeclampsia (15.2%, vs. 3.3%, p<0.001), and were more often obese (23.5% vs. 21.5%, p<0.001). The incidence of CVD increased from 4.1 to 8.6 per 10,000 pregnancies between 2004 and 2012 (p<0.001), then declined to 4.8 per 10,000 in 2023. CAD decreased (1.9 to 0.7 per 10,000; p<0.001), HF increased (1.6 to 3.8 per 10,000; p=0.03), and ICS remained stable (p=0.722) (Figure 1A). The prevalence of associated risk factors increased between 2004 and 2023, which included age over 35 (12.7% in 2004 vs. 16.4% in 2023, p <0.001), obesity (10.8% in 2004 vs. 15.6% in 2023, p<0.001), preeclampsia (2.6% in 2004 vs. 4.2% in 2023, p<0.001), gestational diabetes (1.8% in 2004 vs. 5.9% in 2023, p<0.001), diabetes (0.4% in 2004 vs. 0.6% in 2023, p<0.001), while the prevalence of smokers (18.0% in 2005 vs. 6.8% in 2023, p<0.001) decreased significantly during the same period (Figure 1B). Overall, 43.0% (95% CIl: 39.2% to 46.8%) of the CVD events could be attributed to the nine examined risk factors in the population (Figure 2). Conclusion We observed a decline in the incidence of CVD from 2012 onwards, primarily driven by a reduction in CAD, while the incidence of HF increased during the study period. These trends occurred alongside a rising prevalence of established maternal risk factors, with 43.0% (95% CI: 39.2% to 46.8%) of CVD events attributable to known risk factors. These findings can inform targeted prevention strategies and risk stratification in pregnant women.