Table 3. Classification of maternal cardiovascular risk: World Health Organization (mWHO).

mWHO I (2.4% - 5%)	mWHO II (5.7% - 10.5%)	mWHO II-III (10% - 19%)	mWHO III (19% - 27%)	mWHO IV (40% - 100%)
Small or mild lesions Pulmonary stenosis ASD VSD PDA APVD Mitral valve prolapse Simple lesions, successfully operated Isolated atrial or ventricular extrasystoles	Non-operated ASD, VSD Operated tetralogy of Fallot Non-complex arrhythmias Turner syndrome without aortic dilation	Mild ventricular dysfunction (EF > 45%) Hypertrophic cardiomyopathy Mild to moderate mitral or aortic valve disease Marfan syndrome or other inherited diseases without aortic dilation Bicuspid aortic valve with AoD < 45 mm Operated coarctation of the aorta AVSD	Moderate ventricular dysfunction (EF 30%–45%) Peripartum cardiomyopathy without ventricular dysfunction Mechanical prostheses Systemic RV with or without mild ventricular dysfunction Uncomplicated Fontan circulation Non-operated cyanotic heart disease Other complex heart diseases Severe mitral stenosis	Pulmonary arterial hypertension Systemic ventricular dysfunction (EF < 30% or NYHA class III–IV) Peripartum cardiomyopathy with ventricular dysfunction Serious left heart obstructive lesions Severe systemic right ventricular dysfunction Aortic dilation > 45 mm in Marfan syndrome, > 50 mm in bicuspid aortic valve or other inherited diseases / Turner syndrome

Modified from Balci et al.³² AoD: aortic diameter; APVD: anomalous pulmonary venous drainage; ASD: atrial septal defects; AVSD: atrioventricular septal defect; EF: ejection fraction; NYHA: New York Heart Association; PDA: patent ductus arteriosus; RV: right ventricle; VSD: ventricular septal defects.