Dr. Kevin Walsh:

My role is in congenital heart disease in pregnancy. I jointly run a clinic for maternal heart disease with Dr. Peter McKenna in the Rotunda Hospital.

Advances in treatments for congenital heart disease over the past 50 years have created a cohort of survivors with heart disease that has been either palliated or repaired, but with significant residual problems requiring ongoing medical supervision and repeat catheter and surgical interventions. In the Republic of Ireland there are approximately 1,700 adults alive with complex congenital heart disease and 14,000 adults with simple congenital heart disease.

Many women with repaired congenital heart disease wish to have children. There are now more pregnant women with congenital heart disease than acquired heart disease in the developed world. Pregnancy causes significant changes to cardiovascular physiology, with marked increases in blood volume, cardiac output, namely, increased stroke volume and heart rate, and a reduction in systemic vascular resistance, namely, reduced blood pressure. These changes may be tolerated poorly by women with pulmonary vascular obstructive disease of any cause - for my patients, usually Eisenmenger syndrome, very poorly functioning systemic ventricles or severe left-sided obstructive lesions.

Pregnancy also causes changes in the vascular wall, with a risk of aortic dissection in patients with coarctation of the aorta, Marfan syndrome and Ehlers Danlos syndrome. A pro-thrombotic state exists during pregnancy and women with artificial valves have an increased risk of life-threatening valve thrombosis. The oral anticoagulant Warfarin crosses the placenta and can cause abnormalities in the foetus, known as embryopathy, in the first trimester, haemorrhage and foetal loss throughout pregnancy. Heparin injections are often substituted as it does not cross the placenta but is a less effective anticoagulant. Even if meticulously monitored, the mother is at risk of potentially fatal valve thrombosis.

Preconception counselling is the most important part of the care of these women and should start once puberty is under way. Risk assessment and planning of management during pregnancy for these women is conducted through a joint Mater-Rotunda maternal heart disease multidisciplinary team meeting involving obstetrics, cardiology, anaesthesia and haematology. This results in three to four high risk women per year being delivered in the Mater Hospital rather than in the Rotunda so that they can be monitored more closely and go to intensive care for postpartum monitoring. With this Mater-Rotunda team approach there have fortunately been no maternal deaths in our group of patients with congenital heart disease over the last ten years.

In terms of experience elsewhere a paper published by Drenthen reports a 5% elective termination for congenital heart disease. Colleagues from the UK with large adult congenital heart disease practices report very small numbers of terminations for medical reasons - one or two a year out of a practice of 3,000 women with adult congenital heart disease. This lower than reported termination rate is probably because of good preconception counselling and means that most high risk women either do not get pregnant or know before becoming pregnant that the pregnancy will be very high risk. The terminations were either early following accidental pregnancy or late to save the mother's life. There have been approximately two in the past 13 years.

When termination is required to save the life of a woman with critical illness then it would have to be performed in the adult major teaching hospital with access to intensive care and the relevant specialists. This clearly would not be the case in any of the Dublin public obstetric hospitals. The termination would likely be on an urgent planned basis rather than immediate emergency basis.