Table 1.

European Society of Cardiology modified version of the WHO classification of pregnancy risk with cardiac disease, including congenital diseases. Reproduced with permission⁹

WHO risk class	I	II	III	IV
Risks of pregnancy	No detectable increased risk of maternal mortality and no/mild increase in morbidity.	Small increased risk of maternal mortality or moderate increase in morbidity	Significantly increased risk of maternal mortality or severe morbidity. Expert counselling required. If pregnancy is decided upon, intensive specialist cardiac and obstetric monitoring needed throughout pregnancy, childbirth, and the puerperium.	Extremely high risk of maternal mortality or severe morbidity; pregnancy contraindicated. If pregnancy occurs termination should be discussed. If pregnancy continues, care as for class III.
Conditions/lesions	Uncomplicated, small or mild -pulmonary stenosis -patent ductus arteriosus -mitral valve prolapse Successfully repaired simple lesions -atrial or ventricular septal defect -patent ductus arteriosus, -anomalous pulmonary venous drainage. -Atrial or ventricular ectopic beats, isolated	If otherwise well and uncomplicated: -unoperated atrial or ventricular septal defect -repaired tetralogy of Fallot -most arrhythmias II or III (depending on individual). Repaired coarctation Mild left ventricular impairment Hypertrophic cardiomyopathy Native or tissue valvular heart disease not considered WHO I or IV Marfan syndrome without aortic dilatation Aorta <45 mm in aortic disease associated with bicuspid aortic valve	Mechanical valve Systemic right ventricle Fontan circulation Cyanotic heart disease (unrepaired) Other complex congenital heart disease	Pulmonary arterial hypertension of any cause Severe systemic ventricular dysfunction Severe mitral stenosis, severe symptomatic aortic stenosis Marfan syndrome with aorta dilated >45 mm Aortic dilatation >50 mm in aortic disease associated with bicuspid aortic valve Native severe coarctation