title: The effects of multiple pre- and perinatal risk factors on the occurrence of cerebral palsy. A Norwegian register based study.
abstract: OBJECTIVE
  To examine the effects of multiple risk factors on cerebral palsy (CP).
  
  
  METHODS
  For 176,591 Norwegian infants born 1996-98 and surviving the early neonatal period, data on a number of potential pre- and perinatal risk factors (RFs) for CP were available in the Medical Birth Registry of Norway. For 241 children with CP detailed clinical data were available in the Norwegian CP registry.
  
  
  RESULTS
  In children born at term, 31% had no RF, and none had five or more, while in children born preterm, 9% had no RF in addition to prematurity (p < 0.001 vs. term), and 5% had five or more (p < 0.02 vs. term). In both groups, few children shared the same combination of RFs. Interdependent sequences were more often observed among children born preterm than at term (p < 0.001 vs. term). The most detrimental effect was observed for the combination of maternal disease and low 5-min Apgar score, registered in 11.2% of children with CP. The combination of maternal disease and premature birth had an interaction contrast ratio of 9.25 (CI: 3.56; 14.94), which may be consistent with biological interaction.
  
  
  CONCLUSIONS
  The majority of children with CP born at term most likely had an antenatal or single cause, suggesting individual susceptibility to an injury. The majority of children born preterm, had combinations or sequences of antenatal and perinatal risk factors as the most likely cause of CP.
authors: Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. magne.stoknes@gmail.com
authors: Magne
authors: M
authors: Stoknes
authors: Guro L
authors: GL
authors: Andersen
authors: Areej I
authors: AI
authors: Elkamil
authors: Lorentz M
authors: LM
authors: Irgens
authors: Jon
authors: J
authors: Skranes
authors: Kjell Å
authors: KÅ
authors: Salvesen
authors: Torstein
authors: T
authors: Vik
mesh_terms: D000293:Adolescent; D002547:Cerebral Palsy / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity / Q000639:trends; D005260:Female; D005316:Fetal Distress / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009664:Norway / Q000453:epidemiology; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D015995:Prevalence; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors