Enteral and parenteral energy intake and neurodevelopment in preterm infants: A systematic review.

Objectives: We performed a systematic review to study the effect of enteral and parenteral energy intakes on neurodevelopment (NDV) and cerebral growth in preterm infants, evaluated by NDV scales, magnetic resonance imaging, and head circumference (HC).

Methods: The MEDLINE, Scopus, and ISI Web of Knowledge databases were searched, using the following medical subject headings and terms: "Premature infants," "nutrition," "brain," "nervous system/growth," and "development." A manual search of the reference lists of all eligible articles was conducted. Studies in which the intervention applied was different energy intakes in parenteral nutrition and/or enteral nutrition (EN) during the first weeks of life and NDV was investigated were included. Data regarding nutrition and NDV were collected and analyzed.

Results: Thirty-five studies were included, of which 12 were randomized controlled trials (RCTs) and 23 were cohort studies. Eight RCTs and 15 cohort studies investigated NDV using NDV scales. Of these studies, two RTCs and five cohort studies found no significant difference in NDV evaluated with the Bayley scale between neonates fed high-caloric nutrition and those who received lower energy intakes during early life. In one RCT and two cohort studies was observed a positive effect of EN on NDV. Conversely, in one cohort study, a negative correlation between parenteral energy intake and NDV was described. The analysis of the data from RCTs and cohort studies showed greater HC in the groups receiving aggressive parenteral and total enhanced nutrition, respectively. However, two RCTs and one cohort study did not report any differences in terms of HC. Inconclusive results were reported by studies that investigated cerebral growth by magnetic resonance imaging. The studies observing a positive effect of enhanced nutrition on cerebral and basal ganglia growth, caudate nucleus, cerebellum, and thalami volume investigated only the influence of EN.

Conclusions: The impact of energy intake during early life on NDV remains undefined. A positive impact on brain development encourages the administration of recommended energy intake, mainly by EN, and suggests a more cautious approach to enhanced nutritional strategies by the parenteral route. Further studies are advocated to elucidate the optimal nutritional intervention for preterm infants to improve NDV.