Association between congenital heart defects and small for gestational age

OBJECTIVES. Infants with congenital heart defects may experience inhibited growth during fetal life. In a large case-control study, we addressed the hypothesis that infants with congenital heart defects are more likely to be small for gestational age than infants without congenital heart defects after controlling for selected maternal and infant characteristics. METHODS. Using data from population-based birth defect registries, the National Birth Defects Prevention Study enrolled infants with nonsyndromic congenital heart defects (case subjects) and infants without congenital heart defects or any other birth defect (control subjects). Small for gestational age was defined as birth weight below the 10th percentile for gestational age and gender. Association between congenital heart defects and small for gestational age was examined by conditional logistic regression adjusting for maternal covariates related to fetal growth. RESULTS. Live-born singleton infants with congenital heart defects (case subjects, n = 3395) and live-born singleton infants with no birth defect (control subjects, n = 3924) were included in this study. Case subjects had lower birth weights compared with control subjects. Small for gestational age was observed among 15.2% of case subjects and among only 7.8% of control subjects. Congenital heart defect infants were significantly more likely to be small for gestational age than control infants. CONCLUSIONS. Infants with congenital heart defects are approximately twice as likely to be small for gestational age as control subjects. Small for gestational age status may affect clinical management decisions, therapeutic response, and prognosis of neonates with congenital heart defects. Although the etiology of growth retardation among infants with congenital heart defects is uncertain, further exploration may uncover a common pathogenesis or causal relationship between congenital heart defects and small for gestational age.