title: Effects of gestational age at birth on health outcomes at 3 and 5 years of age: population based cohort study.
abstract: OBJECTIVE
  To investigate the burden of later disease associated with moderate/late preterm (32-36 weeks) and early term (37-38 weeks) birth.
  
  
  METHODS
  Secondary analysis of data from the Millennium Cohort Study (MCS).
  
  
  METHODS
  Longitudinal study of infants born in the United Kingdom between 2000 and 2002.
  
  
  METHODS
  18,818 infants participated in the MCS. Effects of gestational age at birth on health outcomes at 3 (n = 14,273) and 5 years (n = 14,056) of age were analysed.
  
  
  METHODS
  Growth, hospital admissions, longstanding illness/disability, wheezing/asthma, use of prescribed drugs, and parental rating of their children's health.
  
  
  RESULTS
  Measures of general health, hospital admissions, and longstanding illness showed a gradient of increasing risk of poorer outcome with decreasing gestation, suggesting a "dose-response" effect of prematurity. The greatest contribution to disease burden at 3 and 5 years was in children born late/moderate preterm or early term. Population attributable fractions for having at least three hospital admissions between 9 months and 5 years were 5.7% (95% confidence interval 2.0% to 10.0%) for birth at 32-36 weeks and 7.2% (1.4% to 13.6%) for birth at 37-38 weeks, compared with 3.8% (1.3% to 6.5%) for children born very preterm (<32 weeks). Similarly, 2.7% (1.1% to 4.3%), 5.4% (2.4% to 8.6%), and 5.4% (0.7% to 10.5%) of limiting longstanding illness at 5 years were attributed to very preterm birth, moderate/late preterm birth, and early term birth.
  
  
  CONCLUSIONS
  These results suggest that health outcomes of moderate/late preterm and early term babies are worse than those of full term babies. Additional research should quantify how much of the effect is due to maternal/fetal complications rather than prematurity itself. Irrespective of the reason for preterm birth, large numbers of these babies present a greater burden on public health services than very preterm babies.
authors.affiliation: Department of Health Sciences, University of Leicester, Leicester LE1 6TP, UK. eb124@le.ac.uk
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Boyle
authors.forename: Gry
authors.initials: G
authors.lastname: Poulsen
authors.forename: David J
authors.initials: DJ
authors.lastname: Field
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Kurinczuk
authors.forename: Dieter
authors.initials: D
authors.lastname: Wolke
authors.forename: Zarko
authors.initials: Z
authors.lastname: Alfirevic
authors.forename: Maria A
authors.initials: MA
authors.lastname: Quigley
mesh_terms: D001249:Asthma / Q000453:epidemiology; D001827:Body Height / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006304:Health Status; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D009017:Morbidity; D011247:Pregnancy; D047928:Premature Birth; D012044:Regression Analysis; D006113:United Kingdom / Q000453:epidemiology