Pregnancy and native heart valve disease

### Learning objectives Heart disease is the biggest killer of pregnant women in the developed world.1 Likewise, heart disease emerges as the main indirect (non-obstetric) cause of maternal death in low/middle-income countries once basic maternity services and sufficient infrastructure are in place. However, while deaths from complications of ischaemic heart disease, heart failure and sudden arrhythmic death syndrome are the leading causes of cardiac maternal death in the UK,2 rheumatic mitral stenosis is the single most common cause of cardiac maternal mortality in the developing world.3 ,4 Valvular heart disease is not uncommon in women of childbearing age, but there is a paucity of population-based data. Nonetheless, rheumatic valve disease predominates in the developing world, accounting for 50%–90% of maternal cardiovascular complications. In contrast, in the developed world, valve disease is responsible for around 15% of pregnancy-related complications, most commonly as bicuspid aortic valve and mitral valve prolapse.5 This article will review the haemodynamic changes of pregnancy and consider how native valve disease interacts with the physiological demands of pregnancy and delivery. Valve diseases of the normally connected heart are addressed in detail; valve lesions that form part of complex congenital heart disease are beyond the scope of the article. ### Cardiovascular demands of pregnancy and delivery Cardiac output increases during pregnancy by 50% above the non-pregnant state, with most of the rise occurring before the middle of the second trimester and being maintained until the end of pregnancy. The …