Suboptimal nutrition in moderately preterm infants

It is recognised that very preterm infants are at risk of later morbidity, including neurodevelopmental impairment (1), respiratory complications and poor growth (2). However, there is increasing evidence that infants born at later preterm gestations are also at greater risk of such adverse outcomes (3,4), with amalgamated data from follow-up studies showing continuous improvement in IQ scores and decreasing risk of respiratory disease as gestational age at birth increases (5). Moderately preterm infants (32–-34 weeks’ gestation) are at increased risk of respiratory distress syndrome (RDS), sepsis, hypothermia, hypoglycaemia, jaundice and feeding difficulties (6) and account for a high proportion of neonatal unit admissions. Post-discharge, they aremore likely to be rehospitalised with jaundice and feeding difficulties (7). Given that preterm infants are deprived of the rapid intrauterinenutrient accretion and growth that occurs during the third trimester, nutritional factors may influence outcomes, and there is evidence that moderate and late preterm infants experience poor growth in the neonatal period (8). While there are published recommendations for the nutrient requirements of very preterm infants (9), the nutritional requirements of moderate and late preterm infants are less established, although guidance for low birthweight infants <2500 g has been published by the World Health Organization (10). Cumulative nutrient deficits are well described in extremely preterm infants, with poor growth and undernutrition associated with adverse outcomes (11). For moderate and late preterm infants, however, there is a paucity of such data. Nutrition can be modified, so represents a potential target for improving outcomes. We aimed to gain a better understanding of nutrition and growth inmoderate and late preterm infants by carrying out a detailed evaluation of the nutritional care of infants born at 32 + 0 to 34 + 6 weeks’ gestation, between January 1, 2012 and June 30, 2012. Infants of more than 35 weeks’ gestation were excluded, as they are not routinely admitted. Data, including pregnancy and neonatal diagnoses, and daily fluid intakes were extracted from infants’ notes. Daily intakes of ninekeynutrients(energy,protein,carbohydrate,fat,calcium, phosphorous,vitaminA,DandE)associatedwithgrowthand bonehealthwere calculated.Weight andhead circumference datawereconvertedtostandarddeviationscores (SDS)based on UK normative data. Differences between groups were compared using Fisher’s exact test (dichotomous outcomes) orANOVA(continuousoutcomes). Therelationshipbetween nutrition, growth and gestation was explored using linear regression (Stata IC v12.1; Stata Corporation 4905, College Station, TX, USA). Ethical approval was not required as this was a service evaluation. Table 1 shows the study population of 54 infants, with clinical characteristics by gestational age. Of these, 52% were delivered by caesarean section, with RDS being the most common neonatal complication. Mean length of stay was 20.5 days and mean post-conceptional age at discharge was 36 + 4 weeks. Approximately one in six (16%) of the infants had intrauterine growth restriction, (IUGR) with a birthweight below the 10th centile, and seven (14%) infants had a birthweight of less than 1500 g. The mean time to regain birthweight was 10.2 days and mean change in weight SDS between birth and discharge was 0.98. Figure 1 demonstrates the nutritional interventions used in each age group. Nine infants received parenteral nutrition (PN) with a mean duration of 12 days. PN use was more common in infants who were more preterm or