Cardiovascular disease in pregnancy: Prevalence and obstetric outcomes in a Swedish population-based cohort study between 2000 and 2019.

Introduction: The prevalence of cardiovascular disease during pregnancy (cardiovascular disease diagnosed before, during or up to 6 months after childbirth) and the risk of adverse outcomes associated with it have not been previously described in Sweden. This study examined trends in prevalence of cardiovascular disease and its association with maternal and perinatal outcomes, overall and by timing of diagnosis in relation to pregnancy.

Material and methods: This population-based observational retrospective cohort study consisted of women aged 15-49 years who were registered in the Swedish Medical Birth Register 2000-2019. Prevalence was defined as annual diagnosis of cardiovascular disease per pregnant woman as numerator and all pregnant women per year as denominator. Adverse maternal and perinatal outcomes were analyzed using time-dependent Cox regression and Poisson regression models. Outcomes were obtained during and after childbirth up to 1 year postpartum, depending on the outcome.

Results: There were 2 069 107 births to 1 186 137 women (911 101 primiparous). The prevalence of cardiovascular disease among pregnant women in Sweden during 2000-2019 increased from 0.31% to 1.34%, for non-congenital cardiovascular disease, this was primarily driven by arrythmia (0.11%-0.58%). Primiparous women with cardiovascular disease had a higher risk of eclampsia over-all (aHR 4.50, 95% CI 2.01-10.05) and when diagnosed during pregnancy (aHR 3.22, 95% CI 1.21-8.61); admission to psychiatric ward overall (aHR 2.51, 95% CI 1.30-4.83), and when diagnosed during pregnancy (aHR 2.54, 95% CI 1.21-5.34); and one-year mortality when diagnosed before pregnancy (aHR 1.67, 95% CI 1.16-2.42) and when diagnosed postpartum (aHR 6.59, 95% CI 3.38-12.84), compared to those without cardiovascular disease. Children born to women with cardiovascular disease diagnosed both overall and in relation to timing of diagnosis had an increased risk of being born preterm and small for gestational age.

Conclusions: Cardiovascular disease prevalence among pregnant women in Sweden increased during 2000-2019, primarily driven by arrhythmias. In primiparous women, the timing of diagnosis of cardiovascular disease is important for maternal and perinatal outcomes, including when diagnosed postpartum. This calls for awareness among all staff when planning pregnancy and monitoring women with cardiovascular disease throughout pregnancy and in the postpartum period.