UCSF

Abstract Growth Correlates in Preterm Infants Valerie A. Ruth

This research aims to identify growth correlates in preterm infants in order to develop interventions to prevent growth failure. The majority of very low birth weight (VLBW<1500g) infants are affected by extrauterine growth restriction (EUGR), which is defined by a weight less than the 10th percentile at hospital discharge and associated with developmental delay and other long-term sequelae. Research to date has identified no definite causes but some correlations with gestational age, birth weight, and caloric intake. Identifying infants at risk of EUGR in the early stages of hospitalization is critical for interventions to prevent growth failure. This research involved a retrospective chart review of 186 preterm infants born at 27 to 32 weeks gestation admitted and discharged between January 2004 and December 2006 from Lucile Packard Children's Hospital at Stanford University. This dissertation takes the form of three publishable papers. The first paper is a critical review of selected literature on EUGR. Longitudinal and cross sectional studies are reviewed to contrast the merits of each type of analysis for studying EUGR. The second paper analyzes data from the retrospective chart review in order to replicate findings by previous researchers. In the previous study, researchers found that preterm infants born between 32 to 34 weeks gestation with higher baseline heart rates experienced greater weight gain than infants with lower heart rates. These findings were not replicated in the LPCH sample. The third paper aims to determine if weight loss in the first week of life affects subsequent weight gain and length of stay. Using the same sample, results demonstrated that early weight loss did not affect subsequent weight gain or length of hospital stay in the total group. However, in a subgroup of VLBW infants, early weight loss was significantly different between EUGR and non-EUGR infants. Gender differences in growth occurred between EUGR and non-EUGR infants. Future research should further investigate gender and weight loss in the first week of life as potential growth correlates. Identifying these growth correlates in VLBW preterm infants is imperative for developing interventions to reduce EUGR and related morbidities in this vulnerable population.