Table 1.
Maternal cardiovascular risk based on World Health Organization (WHO) classifications (from Thorne et al.10).
| Conditions in which pregnancy risk is WHO class I: risk not significantly higher than the general population • Uncomplicated small or mild pulmonary stenosis, patent ductus arteriosus or mitral valve prolapse • Successfully repaired simple lesions (atrial or ventricular septal defect, patent ductus arteriosus, anomalous pulmonary venous connection) • Isolated atrial and ventricular ectopic beats |
| Conditions in which pregnancy risk is WHO class II (low to moderate risk compared with the general population) – III (significantly higher risk compared with the general population) depending on the individual • Mild left ventricular impairment • Hypertrophic cardiomyopathy • Native or tissue valvular heart disease not considered WHO class I or WHO class IV • Marfan syndrome without aortic dilatation (aortic size < 40 mm) • Aorta < 45 mm in association with bicuspid aortic valve disease • Repaired coarctation of the aorta |
| Conditions in which pregnancy risk is WHO class III: significantly increased risk of maternal morbidity and mortality compared with the general population • Mechanical heart valve • Systemic right ventricle • Fontan circulation • Unrepaired cyanotic heart disease • Other complex congenital heart disease • Aortic dilatation 40–45 mm in Marfan syndrome • Aortic dilatation 45–50 mm in bicuspid aortic valve disease |
| Condititions in which pregnancy risk is WHO class IV: extremely high risk of maternal morbidity and mortality; patients should be counselled against pregnancy • Pulmonary arterial hypertension from any cause • Severe systemic ventricular dysfunction from any cause (ejection fraction < 30%, New York Heart Association class II–IV symptoms) • Previous peripartum cardiomyopathy with any residual impariment of systemic ventricular function • Severe mitral stenosis • Severe symptomatic aortic stenosis • Marfan syndrome with dilated aorta >45 mm • Bisucspid aortic valve disease with dilated aorta >50 mm • Native severe coarctation of the aorta |