Fetal growth and postnatal growth failure in very-low-birthweight infants

Aim: To determine in a cohort of very-low-birthweight (VLBW) infants the incidence of postnatal growth failure and the influence of intrauterine growth and neonatal morbidities on the risk for severe postnatal growth failure (PNGF). Methods: The study was based on analysis of data from the Israel Neonatal Network database on VLBW infants born between 1995 and 2001. Z-score was determined for weight at birth and discharge, and severe PNGF was defined as a decline in z-score of greater than 2. Univariate analysis and multi-linear regression determined the effect of fetal growth and neonatal morbidities on the risk for severe PNGF. Results: Severe PNGF occurred in 10.6% of the cohort. The mean ±SD birthweight (BW) z-score was -0.59±0.74, decreasing to -1.67±0.77 at discharge. The incidence of severe PNGF increased significantly with decreasing BW and gestational age. Each 1-unit increase in z-score BW was associated with a 2.37-fold increased risk for severe PNGF. Severe respiratory distress syndrome, patent ductus arteriosus, sepsis, necrotizing enterocolitis, and bronchopulmonary dysplasia were associated with severe PNGF. Conclusion: Severe PNGF among VLBW infants was markedly influenced by intrauterine growth as well as major morbidities. In the assessment of postnatal growth among VLBW infants, growth status at birth should be considered.