Pregnancy in women with dilated cardiomyopathy (DCM)

This type of cardiomyopathy is different because the heart muscle chambers are not thick, but dilated and enlarged, and there’s some degree of scarring of the heart muscle.

The contraction is not so good and often the conduction system of the heart is involved as well.  Again, this is a genetic disorder.

Patients may have breathlessness and palpitations, they may get tired on exercise and they may experience chest pains. 

In pregnancy the increased workload, increased volume and increased stretch on the heart is going to increase breathlessness. Arrhythmias (heart rhythm problems) may get worse and ventricular function can decline and this is the main worry.

The tablets you usually take if you have dilated cardiomyopathy are ACE inhibitors, such as ramipril, and you cannot take them when pregnant. They  are associated with severe complications for the baby including intra-uterine death and kidney problems.  So you need to stop these before ever considering conceiving. 

After stopping the ACE inhibitor, we always re-echo to make sure there’s been no change in pump function but I have never seen a change in function as a consequence of stopping the ACE inhibitor.

We use betablockers again; this time to reduce the heart’s work. These drugs reduce heart rate and the heart’s oxygen consumption.  We use the diuretic furosemide if people are breathless, aspirin as a mild blood thinner if there’s no arrhythmias, and we use low molecular weight heparin injections if you have arrhythmias or significant enlargement of any of the pumping chambers.

What to expect in pregnancy?

You will have your antenatal care as normal. You will have cardiology reviews more frequently (every four to six weeks) and an echo every visit. Again, we try to deliver women vaginally and we would consider an early delivery if we see a change in ventricular function.

Complications

Complications are far more difficult to predict in dilated cardiomyopathy (DCM). In fact the impact of pregnancy is very unpredictable. I’ve cared for women with familial dilated cardiomyopathy and completely normal pump function at the start of a pregnancy, whose ventricular function has taken a significant downturn as a consequence of pregnancy. But I’ve also looked after women with poor function at the start of pregnancy and function has remained stable during pregnancy.  But as a general rule, if your pump function is good before pregnancy, this is better than if it’s impaired before.

There is some data about pregnancy in dilated cardiomyopathy (DCM). In one study that came out in 2010 they graded mothers depending on their baseline function. They found that arrhythmias may worsen, heart failure and fluid congestion  can be provoked and thromboembolism can occur.  This study also suggested that there was some detriment to long-term outcome. But the numbers were very small, only 36 pregnancies, so it’s very difficult to be sure if long term outcome is truly affected. The babies were also smaller than normal, but some were delivered early so obviously birth weight is less.