World’s first registry of pregnancy and heart disease finds that women in developing countries and those with cardiomyopathy are most at risk.

Adapted from a news release issued by the European Heart Journal

Results from the world's first registry of pregnancy and heart disease have shown that most women with heart disease can go through pregnancy and delivery safely, so long as they are adequately evaluated, counselled and receive high quality care.

However, this is not always the case: women and babies in developing countries are more likely to die than those in developed countries where women are more likely to access better care and counselling before and during pregnancy. Women with cardiomyopathy, a disease of the heart muscle, are also more affected by pregnancy. The findings are published online today in the European Heart Journal.

In 2007 the European Society of Cardiology set up the European Registry on Pregnancy and Heart Disease because deaths during pregnancy among women with heart disease were rising in western countries and it is a major cause of maternal death, yet there was limited understanding about the consequences of heart disease on pregnancy outcome and the best ways of caring for these women. Overall, about 0.9 per cent of pregnant women have some form of heart disease.

Between 2007 and 2011, 60 hospitals in 28 countries enrolled 1321 pregnant women with heart disease to the registry, and collected data on all aspects of the pregnancy and delivery and the mother's heart condition and medication use.

The most common condition, affecting 66 per cent of the women on the registry, was congenital heart disease (CHD) - a problem with the heart's structure and function that is present at birth. A quarter of the women had valvular heart disease (VHD), a disease of one or more of the valves in the heart. Seven per cent had cardiomyopathy (CMP) and two per cent had ischaemic heart disease (IHD), where insufficient blood reaches the heart and can result in problems such as heart attack.

There were clear differences in outcome for mothers and babies by type of heart disease. Women with CMP were more likely to die or to suffer from serious problems such as heart failure and irregular heart beat (ventricular arrhythmias) than women with other conditions. Women with CHD had relatively good outcomes compared to women with other conditions, probably because most of these patients were diagnosed and treated either soon after birth, or long before becoming pregnant, and had benefited from improved treatments and pre-pregnancy counselling.

In cardiomyopathy, because the heart muscle is diseased, there is an increased risk of heart failure during pregnancy as the heart has to work harder. Professor Mark Johnson, one of the paper?s authors from the Department of Surgery & Cancer at Imperial College London, said: "The heart has to pump 50 per cent more blood than usual during pregnancy, a significant increase in work load, which exacerbates an underlying cardiac disease or, in some cases, will bring out a hitherto unrecognised problem."

There were significant differences in outcome between developed and developing countries, although the authors warn that these figures need to be treated with some caution because of the differences in the numbers of women in the different countries. In developing countries 3.9 per cent of women in this study died compared to 0.6 per cent of women in developed countries, and 6.5 per cent of babies died compared to 0.9 per cent in developed countries.

Overall, the study showed that pregnancy in patients with heart disease resulted in one percent of mothers dying, which was 100 times higher than in the normal population of pregnant women. Among women with heart disease 10 in every 1000 died, compared with less than one per 10,000 in the European population of pregnant women without a heart condition. Death of the fetus during pregnancy was five times higher (17 per 1000 dying compared to 3.5 per 1000 of the normal population), and death of the baby within 30 days of birth was 1.5 times higher (6.4 per thousand dying compared to four per 1000 in the normal population). However, these figures varied enormously between developed and developing countries.

The authors conclude that "the vast majority of patients can go safely through pregnancy and delivery as long as adequate pre-pregnancy evaluation and specialised high-quality are during pregnancy and delivery are available." However, they point out that there are important differences.

"This study gives us the essential basic information about the size and extent of the problems facing women with pre-existing heart disease during pregnancy," said Professor Johnson. "This will allow us to start to design interventional studies in high-risk groups with the aim of improving their outcome."

Reference

"Outcome of pregnancy in patients with structural or ischaemic heart disease: results of a registry of the European Society of Cardiology" by Jolien W. Roos-Hesselink et al. European Heart Journal. doi:10.1093/eurheartj/ehs270