Pregnancy in Women With a Fontan Circulation

Abstract

Background: The Fontan circulation results from the Fontan operation,performed for a number of severe congenital heart defects where thereis insufficient ventricular muscle to achieve a biventricular repair. Thisresults in the ventricular chamber (regardless of whether it is a rightor a left ventricle, morphologically) being utilised as the systemic chamber. The venous return to the lungs is achieved by passive flow, with nointervening ventricular pump. Physiologically, these individuals are usuallymildly cyanosed and have reduced exercise capacity on formal testing.The single ventricle is thought to display abnormal mechanics that affectboth systolic and diastolic function. A whole of life experience does notyet exist, as this operation was first described in 1971.Pregnancy and the Fontan circulation-the experience:Worldwide, the experience in the care of these women during pregnancyis small. A recent systematic review has described the main maternalcomplications as being supraventricular arrhythmias, heart failure andembolic events. The rate of livebirths is low (45%) due to a high miscarriage rate, and the babies are often delivered early and small. Bleeding,both ante-and post-partum is a common obstetric complication. TheAustralia and New Zealand Fontan Registry is the largest registry ofindividuals with a Fontan circulation in the world. Insights from thisRegistry will be presented.Pregnancy and the Fontan circulation-management: Thesewomen should all be managed through pregnancy in a multidisciplinaryand tertiary referral setting. Pregnancy management starts with contraceptive advice and pregnancy education. This should commence aroundpuberty, be repeated frequently, and be re-discussed at transition to anadult congenital cardiology service. The importance of a planned conception that follows medical assessment (cardiac and high-risk obstetric, at aminimum, and additionally a haematologist if the woman is anticoagulated) cannot be over emphasised. In some cases, individualised riskassessment may result in advice that conception is contraindicated. It isimportant to support these women and their families through exploration of alternate parenthood opportunities if desired. As pregnancy progresses, the members of the multidisciplinary care team need to expandto include midwives, neonatologists, obstetric, and often also cardiac,anaesthetists and nurses. Women should be monitored in a high acuitysetting (e.g. a coronary care unit) for a minimum of 48 h to ensure diuresis with the post-partum fluid shifts and ideally tolerance of the letdownreflex associated with breastfeeding initiation.Concluding remarks: Although no cases of maternal death in pregnancy were identified in the literature, data on the outcomes of complexcongenital heart disease as a whole do show an increase. Whether pregnancy for these women modulates their longer term outcomes remainsunknown. An international registry is currently being created with thehope of answering the post-partum outcome questions.