Heart Disease in Pregnancy - The Problem

Dateline: 07/19/98

Pregnancy is one of the physiological conditions that places a considerable burden on the heart, forcing it to work harder for a significantly long period - nine months. While a normal heart is quite capable of taking this extra workload right in its stride, a diseased one may not be able to cope. Different kinds of heart disease may cause different problems during pregnancy. In this series of articles I plan to discuss this topic in depth.

The Problem

While there is much regional variation in the incidence of heart disease in pregnancy (0.3 to 3.5 %), an average global figure is 1 %. This means almost one in every hundred women becoming pregnant will have some form of heart disease or the other !

Why is this so worrying ?

• First of all, heart disease is one of the leading causes of maternal mortality. It ranks third after high blood pressure and pulmonary embolism as a cause of death of women during or soon after pregnancy.
• Also, heart disease has an effect on the fetus. For reasons which I will discuss later, the child growing in the womb of a woman with heart disease cannot develop normally and might even fail to survive the pregnancy and delivery process.

Which heart diseases are common during pregnancy ?

Most heart diseases are present even before pregnancy, and become worse - or maybe manifest for the first time - only during gestation.

Valvular heart disease leads the field, with mitral stenosis being the commonest lesion. Not many women with congenital heart disease became pregnant until recently. Today the commonest birth defects seen during pregnancy are patent ductus arteriosus, atrial septal defects and ventricular septal defects. Others like pulmonary valve stenosis, tetralogy of Fallot and coarctation of the aorta make up about 25%. In the near future, we may have to deal with a number of more complex conditions that have been treated surgically. Other heart diseases like coronary artery disease and rhythm disturbances are uncommon in the younger patients in the reproductive age group. Cardiomyopathy is another problem in pregnancy and will be discussed in detail later.

In the next article, we will see how heart disease in pregnancy increases maternal and fetal risks.