Pregnancy complications and long-term risk of cardiovascular events in women with heart disease

Abstract Background/Introduction Women with congenital heart or acquired heart disease are at increased risk of atherosclerotic cardiovascular disease. Pregnancy complications are established risk factors for cardiovascular disease in the general population, but their prognostic value for cardiovascular outcomes in the population with congenital or acquired heart disease is unknown. Purpose To determine the frequency and prognostic value of pregnancy complications for the risk of cardiovascular outcomes in women with congenital or acquired heart disease. Methods This nationwide registry-based cohort study included women in Sweden with heart disease (pulmonary arterial hypertension, congenital heart disease or acquired valvular heart disease) with singleton births registered in the national Medical Birth Register between 1973 and 2014. Exposures of pregnancy complications (preeclampsia/gestational hypertension, preterm birth or birth of an infant small for gestational age) were collected from the Medical Birth Register, and cardiovascular outcomes (mortality and hospitalizations) from the Cause of Death Register and the National Inpatient Register. Cox regression models were performed with time-dependent covariates, to determine the possible prognostic value of the studied pregnancy complications for cardiovascular outcomes including atherosclerotic cardiovascular disease, heart failure and arrythmias after adjustment for major confounding including smoking and body mass index. Results Among the total of 2,134,239 women included from the Medical Birth Register, 2,554 women with 5,568 singleton births were affected by heart disease. Preeclampsia/gestational hypertension affected 5.8% of pregnancies, preterm birth 9.7%, and birth of an infant small for gestational age 2.8%. Preterm birth (adjusted HR 1.91 (95% CI 1.38-2.64)) was associated with an increased risk of maternal all-cause mortality. Preeclampsia/gestational hypertension (adjusted HR 1.64 (95% CI 1.18-2.29)) and preterm birth (adjusted HR 1.56 (95% CI 1.19-2.04)) were associated with an increased risk of hospitalizations for atherosclerotic cardiovascular disease. Conclusions Pregnancy complications were frequent in women with congenital or acquired heart disease. With a median follow-up time of 22 years, preterm birth was associated with a higher risk of cardiovascular mortality, and preeclampsia/gestational hypertension and preterm birth were associated with cardiovascular morbidity. In women with heart disease, pregnancy complications may provide additional information for the risk assessment of future cardiovascular outcomes.Overview of study designPrevalence and risk estimation