When caring for women with structural heart disease (SHD), clinicians face an apparent paradox: most women with SHD are able to complete a pregnancy without complication; however, compared with the general population, maternal risk is increased and SHD remains a major source of maternal morbidity and mortality and poor fetal outcomes.1–4 Identifying those women with SHD who are at increased risk for meaningful complications during pregnancy is critical.

During pregnancy, intravascular volume, stroke volume, heart rate and cardiac output increase, while systemic vascular resistance decreases. During pregnancy, women with congenital heart disease (CHD), cardiomyopathy or valve disease can develop heart failure due to these physiologic changes.

Preconception risk stratification allows women with heart disease to decide if they wish to conceive. Additionally, identifying patients at high risk for cardiac complications provides time to plan the optimal strategy for cardiac surveillance and management during pregnancy. Various models have been developed in order to determine which cardiac conditions place women at highest risk for cardiac complications during pregnancy (table 1).

The European Society of Cardiology's Registry on Pregnancy and Cardiac disease (ROPAC) collected information on 1321 pregnancies of women with structural and ischaemic heart disease in 28 countries. Investigators followed women though pregnancy and reported on maternal and fetal complications.5

Ruys et al6 present the heart failure data from ROPAC. Importantly, the authors report heart failure as a stand-alone end point. This has advantages compared with other studies that report composite end points (death, heart failure, arrhythmia, myocardial infarction and cerebrovascular accidents).1–3 Although composite end points are useful in allowing smaller study size, limitations exist unless each component …