Health outcomes in infancy and childhood of moderate and late preterm infants Pooja Harijan, Elaine M. Boyle * Department of Health Sciences, University of Leicester, 22e28 Princess Road West, Leicester LE1 6TP, UK Keywords: Health Late preterm Moderate preterm Outcomes Preterm summary There has been a long-held belief that outcomes for babies born at moderate and late preterm gestations do not differ substantially from those of infants born at full term. This has recently been challenged by studies highlighting an increased risk of adverse neonatal outcomes, and of poorer cognitive, behavioural and educational outcomes in this population. Data about the effects of birth at moderate and late preterm gestations on later health outcomes are limited, but emerging evidence suggests that ongoing physical health may also be worse in those born just a few weeks before full term. This review summarises the available evidence, considers the factors influencing health outcomes and discusses the implications for the planning and provision of children’s health care services. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Historically, interest in health outcomes of preterm infants has been centred on very preterm infants, i.e. those born at <32 weeks of gestation. This is understandable, as this group includes those babies for whom severity of neonatal illness is likely to be greatest and in whom adverse long-term outcomes are most likely to occur. 1e4 Most neonatologists, therefore, ‘routinely’ follow up infants born at <32 weeks until around 2 years of age and most research studies to date have been concentrated on this population. By contrast, few centres have a programme of ongoing surveillance for more mature preterm infants, as their outcomes have been assumed to be similar to those of term-born infants. In the UK there is currently no routine neonatal data collection for this group. However, it has become apparent over recent years, from retrospective analyses of large cohorts in North America, that the risk of significant neonatal morbidity is greater in moderate (32e33 weeks) and late (34e36 weeks) preterm infants compared with infants born at 37 weeks of gestation. 5e8 Published data on later health outcomes in children who have been born at 32e36 weeks of gestation are relatively few, but emerging evidence suggests that for some, health problems may persist into later infancy and childhood. 9 2. Hospitalisation during infancy and childhood Increased likelihood of readmission of late preterm infants to hospital following discharge from neonatal care is well documented. In a US study, 4.4% of 2153 infants born at 34 to 36 þ6 weeks of gestation were readmitted within the first 15 days after discharge, compared with 2.0% of 30 261 infants born at >37 weeks. 10 Following early neonatal discharge in a UK cohort, read- mission in the first month occurred in 6.3% of infants born at 35e37 weeks of gestation compared with 3.4% and 2.4% respectively of those born at 38e40 and >40 weeks. 11 Jain and Cheng found that emergency department attendances in the neonatal period were also increased in late preterm infants, with the greatest proportion of these being in infants born at 36 weeks of gestation. 12 Jaundice has consistently been found to be the most frequent reason for hospital readmission in the first month of life. 10,13,14 Other common reasons are infection, 14 feeding difficulties and dehydration. 5 An important risk factor for early post-discharge morbidity appears to be failure to successfully establish adequate breastfeeding, 13,15 but early hospital discharge has also been implicated. 14 Hospitalisation beyond the neonatal period has been less well investigated. Escobar found that late preterm infants were more likely to require at least one hospital admission within the first six months after birth. 5 McLaurin et al. 16 showed that health care- related costs were higher for late preterm infants than for term born infants, with the greatest costs being related to hospital inpatient admissions; regardless of the timing of discharge from neonatal care, infants born late preterm were almost twice as likely to have received inpatient hospital care during the first year. Secondary analysis of data from the Millennium Cohort Study (MCS), a UK nationally representative prospective cohort study, examined parental reports of their children’s hospital admissions. Compared with infants born at full term (39e41 weeks of gesta- tion), the odds of having three or more admissions within the first nine months of life was higher for both moderate preterm [adjusted * Corresponding author. Tel.: þ44 (0) 116 252 5447. E-mail address: eb124@leicester.ac.uk (E.M. Boyle). Contents lists available at SciVerse ScienceDirect Seminars in Fetal & Neonatal Medicine journal homepage: www.elsevier.com/locate/siny 1744-165X/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.siny.2012.02.002 Seminars in Fetal & Neonatal Medicine 17 (2012) 159e162