title: Pre-, peri- and neonatal risk factors for autism.
abstract: OBJECTIVE
  To identify pre-, peri- and neonatal risk factors for pervasive developmental disorders (PDD).
  
  
  METHODS
  We searched the Medline database through March 2011 for relevant case-control and population-based studies on pre-, peri- and neonatal hazards related to PDD, including autism. We identified 85 studies for this review. Data were extracted systematically and organized according to risk factors related to family history, pregnancy, gestational age, delivery, birth milestones and the neonate's condition at birth.
  
  
  RESULTS
  During the prenatal period, risk factors for PDD were advanced maternal or paternal ages, being firstborn vs. third or later, maternal prenatal medication use and mother's status as foreign born. During the perinatal and neonatal periods, the risk factors for PDD were preterm birth, breech presentation, planned cesarean section, low Apgar scores, hyperbilirubinemia, birth defect and a birthweight small for gestational age. The influence of maternal pre-eclampsia, diabetes, vomiting, infections and stress during pregnancy requires further study in order to determine risk for PDD.
  
  
  CONCLUSIONS
  Despite evidence for the association of some pre-, peri- and neonatal risk factors associated with PDD, it remains unclear whether these risks are causal or play a secondary role in shaping clinical expression in individuals with genetic vulnerability. A plausible hypothsesis is that improvements in obstetric and neonatal management have led to an increased rate of survivors with pre-existing brain damage. Given the variety of risk factors, we propose that future studies should investigate combinations of multiple factors, rather than focusing on a single factor.
authors.affiliation: Department of Child and Adolescent Psychiatry, Pitié-Salpêtrière Universitary Hospital, Paris, France. vincent.guinchat@psl.aphp.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Guinchat
authors.forename: Poul
authors.initials: P
authors.lastname: Thorsen
authors.forename: Claudine
authors.initials: C
authors.lastname: Laurent
authors.forename: Christine
authors.initials: C
authors.lastname: Cans
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bodeau
authors.forename: David
authors.initials: D
authors.lastname: Cohen
mesh_terms: D001034:Apgar Score; D001724:Birth Weight; D002659:Child Development Disorders, Pervasive / Q000209:etiology*; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007744:Obstetric Labor Complications; D011247:Pregnancy; D011248:Pregnancy Complications; D012307:Risk Factors