FEMALES who experienced five adverse pregnancy outcomes have an increased risk of ischaemic heart disease up to 46 years after delivery, according to findings of a national cohort study. More than 2 million females in Sweden were included in the study, which investigated the relationship between five major adverse pregnancy outcomes (small for gestational age, gestational diabetes, preterm delivery, pre-eclampsia, and other hypertensive disorders of pregnancy) and ischaemic heart disease. Participants were followed for up to 46 years, permitting the assessment of lifetime risk of ischaemic heart disease.
“Adverse pregnancy outcomes are extremely common,” said Casey Crump, Professor of Epidemiology in the Department of Population Health Science and Policy, Icahn School of Medicine, Mount Sinai, New York, USA, with “nearly 30% of women having one during their reproductive years.” Previous research has investigated each of these adverse pregnancy outcomes and their related risk to ischaemic heart disease, but they have rarely been examined in the same cohort.
During the total study period of 53.6 million person-years, the researchers identified ischaemic heart disease in 3.8% of the cohort. Crump and colleagues noted that females who had experienced any of the five major adverse pregnancy outcomes were at an increased risk of ischaemic heart disease 10 years after delivery. The strongest association was between other hypertensive disorders and ischaemic heart disease (adjusted hazard ratio [aHR]: 2.09; 95% confidence interval [CI]: 1.77–2.46), followed by preterm delivery (aHR: 1.72; 95% CI: 1.50–1.90). Interestingly, the strong association between other hypertensive disorders and ischaemic heart disease remained elevated at 30–46 years post-delivery (aHR: 1.47; 95% CI: 1.30–1.66).
Despite these results, the authors addressed a number or limitations, namely the inability to address the influence of cofounders such as maternal smoking and obesity. Furthermore, the study was limited to Sweden, meaning future replication in other countries would be valuable.
Overall, “adverse pregnancy outcomes are an early signal for future heart disease risk, and they can help identify high-risk women much earlier, and thus enable earlier preventive actions to improve their long-term outcomes,” said Crump, suggesting that “these women need more aggressive screening.” The data generated by this study suggests all major adverse pregnancy outcomes should be recognised as lifelong risk factors for ischaemic heart disease. Thus, these females should be considered for early preventative evaluation and long term risk reduction.