Controlled comparison of early growth velocities of IUGR and NON-IUGR VLBW infants WHO received early aggressive parenteral nutrition

OBJECTIVE: Early aggressive parenteral nutrition is the preferred way of nutritional management for VLBW infants. However, it is not known whether IUGR infants and those without IUGR grow up at a similar velocity postnatally or not. Protein synthesis may be refractory in chronically IUGR infants, therefore this kind of feeding may not be appropriate and a different feeding protocol may be required. In this study, we aimed to determine growth velocities of IUGR and non-IUGR infants until discharge and for the first 28 days; postnatal maximum weight losses, ages to regain birth weights; whether nutritional characteristics and major morbidities exert effects on growth velocities or not; perform subgroup analysis for ELBW infants and compare biochemical characteristics.STUDY DESIGN: Retrospective, clinical case-controlled study.PATIENTS AND METHODS: The files of very low birth weight (<1500 g) infants were assessed among ones followed in Dokuz Eylül University Neonatal Intensive Care Unit between February 2006- September 2009. Infants without full records, with congenital malformations, chromosomal abnormalities, congenital infections and metabolic diseases, and those who died before 28 days of life were excluded. Infants with a ponderal index below 10. percentile (IUGR) and those above 10. percentile were compared in terms of growth velocities for the first 28 days of life and at discharge; maximal postnatal weight losses and time to regain birth weight. Age at initial feeding, at full enteral feeding, at full enteral nutrition; and major morbidities (BPD, symptomatic PDA, late-onset sepsis, severe IVH, NEC) were assessed whether they exerted effects on growth velocities. A subgroup analysis was performed for extremely low birth weight infants (<1000 g). BUN, serum creatinine, serum electrolytes, liver function tests, serum albumin and protein levels were compared between the two groups at the third, seventh and twenty-eighth (or pre-discharge assessment if discharged before 28 days) days of life.RESULTS: Among 204 VLBW infants followed in the Neonatal Intensive Care Unit during aforementioned period of time, 99 infants (36 IUGR, 63 non-IUGR) were recruited for the study. Mean gestational ages of IUGR and non-IUGR infants were 30,3 (25-37) and 29,9 (24-36) respectively. The IUGR group included 64% females and 36% males, whereas the non-IUGR group included 50% females and 50% males. Mean birth weights, lengths, head circumferences of the IUGR and non-IUGR groups were 1129 g (610-1473) and 1115 g (645-1490); 38,7 cm (32-44) and 35,9 cm (30-41) ; 27,3 cm (23-34) and 26,4 cm (20-30), respectively. Birth length was the single demographic parameter to differ significantly ? higher for IUGR infants. The day of discharge and discharge weights were not significantly different. At the time of discharge, 86% of the IUGR group and 81% of the non-IUGR group had extrauterine growth retardation. Sepsis was the only major morbidity to differ significantly. There were no significant differences in terms of nutritional and initial weight loss characteristics. Growth velocities at discharge for IUGR and non-IUGR infants were 21,8 ± 5,4 and 20,0 ± 5,4 g/kg/d; and at 28 days were 15,6 ± 5,6 and 16,1 ± 5,1 g/kg/d, neither having statistical significance, nor for ELBW IUGR and non-IUGR infants. IUGR infants had significantly higher growth velocities at discharge in the absence of morbidities. Nutritional characteristics did not exert effect on growth velocities. Signs of TPN toxicities did not develop in either groups.CONCLUSIONS: IUGR and non-IUGR VLBW and ELBW infants on early, aggressive TPN did not differ in terms of growth velocities. However, IUGR VLBW infants had significantly higher growth velocities at discharge in the absence of morbidities. At the time of discharge, 86% of the IUGR group and 81% of the non-IUGR group had extrauterine growth retardation. Early, aggressive TPN is considered to be safe and efficacious for IUGR infants.