Heart Disease Is Lead Cause of Death in Pregnancy

September 13, 2012

September 13, 2012 (London, United Kingdom) — Pregnant women who have heart disease have a 100-fold higher mortality than the normal pregnant population, according to new data from the first-ever formal registry on pregnancy and heart disease [1].

The registry, published online in the European Heart Journal on September 11, 2012, was set up by the European Society of Cardiology, as the first step to address the rising death rate of women with heart disease during pregnancy. The authors note that overall, about 0.9% of pregnant women have some form of heart disease.  

One of the investigators involved, Dr Mark Johnson (Imperial College London, UK) commented to heartwire : "Heart disease is the biggest cause of death in pregnant women, having three times the mortality rate of [deep vein thrombosis] DVT and six times that of hemorrhage. While awareness of this issue is rising, there is still more work to be done to ensure that pregnant women with risk factors for heart disease are investigated appropriately."

Good Care Can Make a Big Difference

Johnson said one of the most important messages was that if a woman has preexisting heart disease and receives good care, the complication rate is very low. "The key factor is to be seen by a specialist before she gets pregnant, so that she can get on all the right medications and receive regular monitoring throughout the pregnancy."

He added that a major problem is diagnosing heart disease in pregnancy, as the symptoms often mimic general symptoms of pregnancy--eg, breathlessness, tiredness, and heartburn. "And heart disease is often not at the front of the health professional's mind when caring for a pregnant woman."

He called for a low threshold for investigation, especially now, as more pregnant women are older, overweight and have preexisting conditions such as diabetes or hypertension. "If a doctor or midwife sees a pregnant woman with these risk factors, and she is complaining of chest pain or shortness of breath, they should be thinking about cardiac disease and refer her for further investigation."

The registry, which was compiled between 2007 and 2011, includes 1321 pregnant women with heart disease from 28 countries. Underlying cause of heart disease was congenital in 66% of the women and valvular in 25%; 7% had a cardiomyopathy and 2% had ischemic heart disease.

Results showed a maternal mortality of 1%, compared with 0.007% in the normal population. However, clear differences were found in outcomes with respect to the underlying cardiac diagnosis, with cardiomyopathy associated with the worst prognosis, and these women also had higher rates of heart failure and ventricular arrhythmias. Postpartum hemorrhage occurred more often in patients with valvular heart disease, probably related to their high use of oral anticoagulants.

As may be expected, there was also a large difference between mortality rates in developing (3.9%) and developed (0.6%) countries.

Death of the fetus during pregnancy was five times higher in women with heart disease (1.7% vs 0.35% in the normal population), and death of the baby within 30 days of birth was 1.5 times higher (0.6% vs 0.4%). However, these figures again varied enormously between developed and developing countries.

Outcomes for Women With Heart Disease Compared With the Normal Pregnant Population

Outcome Normal population (%) Congenital heart disease (%) Valve disease (%) Cardiomyopathy (%) Ischemic heart disease (%)
Maternal mortality 0.007 0.5 2.1 2.4 0
Heart failure 0 8.0 18 24 8.0
C-section 23 38 42 58 60
Fetal death 0.35 0.5 3.9 4.5 4.0

Johnson noted that some women do not realize they have a heart condition until it makes itself obvious during pregnancy. For example, cardiomyopathies may not develop until pregnancy. And some patients with congenital problems diagnosed in childhood may be lost to follow-up.

He also pointed out that there is the additional issue in certain countries, such as Egypt and India, in that women are under huge pressure to have children, and even if they are aware of a heart problem they might not seek help for fear of being discouraged from becoming pregnant.

Valvular heart disease as a result of rheumatic fever is also much more common in developing countries, but in the UK and other developed countries it is mostly limited to the immigrant population.

The authors add that the pregnancy registry will continue to enroll patients over the next few years. The resulting database should allow firmer conclusions to be drawn on the specific groups and improved management plans.