Pregnancy in women with congenital heart disease: complications and mechanisms

In part I of this thesis we described the incidence of cardiovascular complications, new predictors of cardiovascular complications during and after pregnancy, and we assessed the impact of pregnancy on cardiac function and remodeling in women with congenital heart disease (CHD). We showed that cardiovascular complications occur in 10.3% of the pregnancies in the ZAHARA II study and that a Nt-proBNP level > 128 pg/mL at 20 weeks gestation was independently associated with the occurrence of cardiovascular events later in pregnancy. This may provide a helpful additional tool for doctors caring for these patients. We also demonstrated that women with CHD tolerate pregnancy well with respect to cardiac function, without any permanent damage. This is valuable information during preconception counseling of these women. However, women with a cardiovascular event during pregnancy are prone to develop cardiovascular events during the first year post-partum, which underlines the importance of post-partum follow-up. In part II of the thesis we investigated if maternal cardiac dysfunction plays a role in the pathogenesis of obstetric and neonatal complications. We found differences in uteroplacental Doppler flow (UDF) parameters between women with CHD and healthy pregnant women. Cardiac dysfunction was associated with an abnormal UDF pattern, while abnormal UDF was associated with neonatal complications. These are important findings, which suggest that maternal cardiac dysfunction is one of the contributors to the occurrence of defective placentation and impaired placenta function, with subsequent poor pregnancy outcome. More fundamental research is required to provide a better understanding of the mechanisms involved.