title: Age of sitting unsupported and independent walking in very low birth weight preterm infants with normal motor development at 2 years.
abstract: OBJECTIVE
  The aims of this study is to (i) determine the age of sitting unsupported and independent walking in preterm infants with birth weight under 1500 g (very low birth weight, VLBW); (ii) estimate differences between VLBW children and a reference population and (iii) estimate the association between clinical characteristics and late age at sitting and walking.
  
  
  METHODS
  A longitudinal study was conducted of a cohort of 876 children with VLBW. The World Health Organization (WHO) motor development study population was used as a reference. Ages for both skills were established by interview with parents. Means were compared with t-test, ANOVA and Bonferroni adjustment where appropriate.
  
  
  RESULTS
  The inclusion criteria were complied with 694 patients; 50% of VLBW sat at 7 m corrected age (CA) and walked at 13 m CA. Both motor skills were acquired later (7.3 +/- 1.5 and 13.6 +/- 2.8 m) compared with the control group (6 +/- 1.1 and 12.1 +/- 1.8 m). Weight or head circumference at birth below the 10th percentile or the presence of bronchopulmonary dysplasia were associated with delayed acquisition of both skills.
  
  
  CONCLUSIONS
  Very low birth weight infants typically sit unsupported and walk later than term infants. Tables describing reference values for milestones acquisition for different categories of infants (gestational age, birth weight and other determinants) may contribute to inform the decision making process on access to available resources.
authors.affiliation: Department of Neonatology, Hospital Universitario 12 de Octubre, SAMID, Madrid, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Marín Gabriel
authors.forename: C R
authors.initials: CR
authors.lastname: Pallás Alonso
authors.forename: J
authors.initials: J
authors.lastname: De La Cruz Bértolo
authors.forename: S
authors.initials: S
authors.lastname: Caserío Carbonero
authors.forename: M
authors.initials: M
authors.lastname: López Maestro
authors.forename: M
authors.initials: M
authors.lastname: Moral Pumarega
authors.forename: C
authors.initials: C
authors.lastname: Alonso Díaz
authors.forename: D
authors.initials: D
authors.lastname: Lora Pablos
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000254:growth & development / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000254:growth & development / Q000502:physiology*; D007407:Interviews as Topic; D008137:Longitudinal Studies; D009048:Motor Skills; D004856:Postural Balance / Q000502:physiology*; D012016:Reference Values; D016138:Walking / Q000502:physiology* / Q000706:statistics & numerical data