Influence of birthweight on perinatal outcome in fetuses with antenatal diagnosis of congenital heart disease.

Abstract

The incidence of congenital heart disease (CHD) accounts for the largest proportion of infant mortality attributable to birth defects. Associations have previously been reported between CHD and low birthweight. Low birthweight is independently associated with adverse outcome and has characteristically been calculated using population-based charts. This aim of this study was to determine the incidence of small for gestational age (SGA) in fetuses with CHD utilizing customized birthweight centiles and to determine the effect of SGA on adverse outcome. A retrospective cohort study was performed between 2006 and 2011. All singleton fetuses with CHD, with no associated karyotype or structural extra-cardiac abnormalities, who delivered at St Thomas's Hospital, London, were included. Population and customized birthweight centiles were calculated and perinatal outcome data were recorded. A total of 17% of fetuses with CHD had a birthweight centile <10th when population centiles were used, and 25% when customized birthweight centiles were applied. There was no correlation between SGA and increased adverse perinatal outcome. A high proportion of fetuses with CHD are classified as SGA when both population and customized birthweight centiles are used. SGA does not correlate with adverse outcome in the perinatal period. The cardiac defect therefore appears to be the main determinant of outcome and not the size of the baby at delivery.