title: Prevalence and predictors of idiopathic asymmetry in infants born preterm.
abstract: BACKGROUND
  An idiopathic asymmetry in posture of the head is recognized as a risk factor to develop a deformational plagiocephaly (DP). In our neonatal follow-up clinic, an IA is often observed in infants born preterm at term-equivalent age (TEA).
  
  
  OBJECTIVE
  To explore (1) the prevalence of an idiopathic asymmetry in 192 infants (gestational age ≤32.0 weeks) at TEA and 6 months corrected age (CA), (2) whether demographical, perinatal, and medical factors were predictors of the asymmetry, and (3) differences in motor maturation between infants with and without asymmetry.
  
  
  METHODS
  In a retrospective study, frequencies of idiopathic asymmetry and DP, putative predictors, and Alberta Infant Motor Scale scores at 6 months CA were abstracted and analyzed with Chi(2), Mann-Whitney, logistic regression and T-test.
  
  
  RESULTS
  The prevalence rate of a positional preference of the head at TEA was 44.8% (n=86), 10.4% (20/192) had a DP at TEA and 13% (25/192) at 6 months CA. Positional preference, multiple birth and male gender predicted the presence of DP (p<.05, odds ratio 3.0, 3.2, and 3.1 respectively). Gross motor maturity at 6 months CA was less developed in infants with a positional preference at TEA compared to preterm norms (p=0.01).
  
  
  CONCLUSIONS
  The high prevalence of a positional preference in infants born preterm at term equivalent age requires extra alertness to prevent the development of a deformational plagiocephaly, especially in boys and twins. Although, considering the lower prevalence of plagiocephaly at 6 months CA, therapists should be aware of over treating these infants.
authors: Child Development and Exercise Center, Division of Pediatrics, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands. j.nuysink@umcutrecht.nl
authors: Jacqueline
authors: J
authors: Nuysink
authors: Ingrid C
authors: IC
authors: van Haastert
authors: Maria J C
authors: MJ
authors: Eijsermans
authors: Corine
authors: C
authors: Koopman-Esseboom
authors: Janjaap
authors: J
authors: van der Net
authors: Linda S
authors: LS
authors: de Vries
authors: Paul J M
authors: PJ
authors: Helders
mesh_terms: D002657:Child Development / Q000502:physiology*; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D009420:Nervous System / Q000254:growth & development; D009426:Netherlands / Q000453:epidemiology; D049068:Plagiocephaly, Nonsynostotic / Q000175:diagnosis* / Q000453:epidemiology*; D011187:Posture; D011237:Predictive Value of Tests; D015995:Prevalence; D011597:Psychomotor Performance / Q000502:physiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D014427:Twins