title: Pregnancy and birth complications in autism and liability to the broader autism phenotype.
abstract: OBJECTIVE
  To understand better the relationship between pregnancy and birth complications and genetic factors in autism.
  
  
  METHODS
  The sample included 78 children with an autism spectrum disorder and 88 unaffected siblings. A standardized interview was used to ask mothers about the pregnancy and birth of each child, and an overall index reflecting freedom from complications (termed "optimality") was determined. The presence of autism-like traits (termed the "broader autism phenotype") in second- and third-degree relatives was ascertained by reports from multiple informants. The pro-. portion of relatives with the broader autism phenotype, corrected for degree of relation, was used as an index of family loading.
  
  
  RESULTS
  Children with autism spectrum disorders have lower optimality (higher rates of complications) than unaffected siblings. High family loading for the broader autism phenotype is associated with higher rates of complications in unaffected siblings. Family loading was not significantly associated with complications in affected siblings in this sample. Overall, these findings argue against complications being a direct cause of autism, as one would expect to find the most complications in sporadic cases (i.e., in children without a positive family history).
  
  
  CONCLUSIONS
  Increased rates of birth and pregnancy complications are likely secondary to familial factors associated with autism.
authors.affiliation: Department of Paediatrics, McMaster University, Hamilton, Ontario, Canada. zwaigenb@mcmaster.ca
authors.forename: Lonnie
authors.initials: L
authors.lastname: Zwaigenbaum
authors.forename: Peter
authors.initials: P
authors.lastname: Szatmari
authors.forename: Marshall B
authors.initials: MB
authors.lastname: Jones
authors.forename: Susan E
authors.initials: SE
authors.lastname: Bryson
authors.forename: Joanna E
authors.initials: JE
authors.lastname: MacLean
authors.forename: William J
authors.initials: WJ
authors.lastname: Mahoney
authors.forename: Giampiero
authors.initials: G
authors.lastname: Bartolucci
authors.forename: Lawrence
authors.initials: L
authors.lastname: Tuff
mesh_terms: D001321:Autistic Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D002648:Child; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005828:Genetics, Population; D006801:Humans; D008297:Male; D007744:Obstetric Labor Complications / Q000175:diagnosis* / Q000523:psychology; D010641:Phenotype; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis* / Q000523:psychology; D012307:Risk Factors