Fetal growth in infants with cardiovascular malformations

Abstract

Patterns of fetal growth in infants with congenital cardiovascular malformations (CVM) had not been studied previously. This research characterized the extent and pattern of fetal growth differences between live-born control infants and those with transposition of the great arteries (TGA), tetralogy of Fallot (TF), hypoplastic left heart syndrome (HLH), and coarctation of the aorta (CA). A sample of 276 controls and 251 cases with TGA, TF, HLH, and CA were selected from the Baltimore-Washington Infant Study, and detailed anthropometric and gestational age data were abstracted at 26 birth hospitals from the medical records of study infants and mothers. The primary analysis tested the multivariate hypothesis that, after controlling for covariates, fetal growth is different across diagnostic class, as reflected in the joint distribution of: birth weight, birth length, head circumference, ponderal index, and power index (a non-linear function relating head volume to birth weight). The remaining analyses evaluated multivariate and univariate case-control differences in neonatal anthropometry specific to individual diagnostic groups. Two new anthropometric indices were developed which reflect neonatal size and shape, and which correlate highly with multivariate case-control discriminators. Clear and convincing evidence of case-control differences in fetal growth were found. TGA was associated with normal birth weight, but lesser mean head circumference and birth length, relative to birth weight. Infants with TF were smaller than controls in all measured dimensions, but important shape differences were not noted. Infants with HLH were much smaller than controls in all measured dimensions, and head volume was disproportionately small, relative to birth weight. CA was associated with lower mean birth weight, shorter mean birth length, and greater mean head volume, relative to birth weight. These findings are most consistent with the argument that malformation-specific alterations in the fetal circulation predict abnormal gross anatomic patterns of development, as reflected in neonatal anthropometric measurements.