title: Prevalence of suspected developmental delays in early infancy: results from a regional population-based longitudinal study.
abstract: BACKGROUND
  Prevalence estimates on suspected developmental delays (SDD) in young infants are scarce and a necessary first step for planning an early intervention. We investigated the prevalence of SDD at 4, 6 and 12 months, in addition to associations of SDD with gender, prematurity and maternal education.
  
  
  METHODS
  This study is based on a Norwegian longitudinal sample of 1555 infants and their parents attending well-baby clinics for regular health check-ups. Moreover, parents completed the Norwegian translation of the Ages and Stages Questionnaires (ASQ) prior to the check-up, with a corrected gestational age being used to determine the time of administration for preterm infants. Scores ≤ the established cut-offs in one or more of the five development areas: communication, gross motor, fine motor, problem solving and personal-social, which defined SDD for an infant were reported. Chi-square tests were performed for associations between the selected factors and SDD.
  
  
  RESULTS
  According to established Norwegian cut-off points, the overall prevalence of SDD in one or more areas was 7.0 % (10.3 % US cut-off) at 4 months, 5.7 % (12.3 % US cut-off) at 6 months and 6.1 % (10.3 % US cut-off) at 12 months. The highest prevalence of SDD was in the gross motor area at all three time points. A gestational age of < 37 weeks revealed a significant association with the communication SDD at 4 months, and with the fine motor and personal social SDD at 6 months. Gender was significantly associated with the fine motor and problem solving SDD at 4 months and personal- social SDD at 6 months: as more boys than girls were delayed. No significant associations were found between maternal education and the five developmental areas of the ASQ.
  
  
  CONCLUSIONS
  Our findings indicate prevalence rates of SDD between 5.7 and 7.0 % in Norwegian infants between 4 and 12 months of age based on the Norwegian ASQ cut-off points (10.3-12.3 %, US cut-off points). During the first year of life, delay is most frequent within the gross motor area. Special attention should be paid to infants born prematurely, as well as to boys. Separate norms for boys and girls should be considered for the ASQ.
authors.affiliation: National Network for Infant Mental Health in Norway, Center for Child and Adolescent Mental Health, Eastern and Southern Norway, Oslo, Norway. Lisbeth.valla@r-bup.no.
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Valla
authors.affiliation: Center for Child and Adolescent Mental Health, Eastern and Southern Norway, Oslo, Norway. tore.wentzel-larsen@r-bup.no.|Norwegian Center for Violence and Traumatic Stress Studies, Oslo, Norway. tore.wentzel-larsen@r-bup.no.
authors.forename: Tore
authors.initials: T
authors.lastname: Wentzel-Larsen
authors.affiliation: Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway. dag.hofoss@medisin.uio.
authors.forename: Dag
authors.initials: D
authors.lastname: Hofoss
authors.affiliation: National Network for Infant Mental Health in Norway, Center for Child and Adolescent Mental Health, Eastern and Southern Norway, Oslo, Norway. kari.slinning@r-bup.no.|Department of Psychology, University of Oslo, Oslo, Norway. kari.slinning@r-bup.no.
authors.forename: Kari
authors.initials: K
authors.lastname: Slinning
mesh_terms: D002658:Developmental Disabilities / Q000453:epidemiology*; D004522:Educational Status; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D008137:Longitudinal Studies; D008297:Male; D009664:Norway / Q000453:epidemiology; D010290:Parents; D015995:Prevalence; D017678:Sex Distribution; D011795:Surveys and Questionnaires