Evidence of perinatal complications associated with autism

    1.  van Handel M, Swaab H, de Vries LS, Jongmans MJ.Long-term cognitive and
    behavioral consequences of neonatal encephalopathy following perinatal asphyxia:
    a review. Eur J Pediatr. 2007 Apr 11; [Epub ahead of print].
    "Most outcome studies have focused on neurological functioning and
    severe deficits in young children (<4 years).  In general, very few children
    with mild encephalopathy show neurological impairments or have
    developed severe mental or motor retardation at preschool age. ... Only a
    few studies looked at the behavioral consequences of NE.  Those studies
    found elevated rates of hyperactivity and autism in children with moderate
    NE."

    2.  Kolevzon A, Gross R, Reichenberg A.Prenatal and perinatal risk factors for
    autism: a review and integration of findings. Arch Pediatr Adolesc Med. 2007 Apr;
    161(4):326-33.
    "According to our review, 3 parental characteristics and 2 obstetric
    conditions emerge as potential risk factors for autism: namely, paternal
    age, maternal age, maternal immigration, growth restriction, and newborn
    hypoxia. In analyses that adjusted for confounding variables, these factors
    usually remained statistically significant."

    3.  Maimburg RD, Vaeth M. Perinatal risk factors and infantile autism. Acta
    Psychiatr Scand. 2006 Oct;114(4):257-64.
    " We also found strong associations between children with infantile
    autism and mothers with foreign citizenship, children with congenital
    malformations and children who needed treatment at Neonatal Intensive
    Care Unit (NICU) after birth. When the caesarean sections were
    categorized into scheduled and unscheduled procedures, we found only
    scheduled caesarean sections to be associated with infantile autism."

    4.  Badawi N et al. Autism following a history of newborn encephalopathy: more
    than a coincidence? Dev Med Child Neurol. 2006 Feb;48(2):85-9.
    "... in a population-based study of moderate and severe term newborn
    encephalopathy (NE) in Western Australia ...infants with NE were 5.9 (95%
    CI 2.0–16.9) times more likely to be diagnosed with an ASD than controls...
    this was not an expected association at the outset of the study"

    5. Larsson HJ et al. Risk factors for autism: perinatal factors, parental psychiatric
    history, and socioeconomic status. Am J Epidemiol. 2005;161:916-25.
    "In the unadjusted analyses, breech presentation, lowApgar score (less
    than or equal 7) at 5 minutes, low birth weight (less than or equal 2,500 g),
    gestational age at birth of less than 35 weeks, and being small for
    gestational age were associated with a statistically significantly increased
    risk of autism..."

    6. Gillberg C, Cederlund M. Asperger syndrome: familial and pre- and perinatal
    factors. J Autism Dev Disord. 2005 Apr;35(2):159-66.
    "Five children had had an Apgar score of 6 or under at 1, 5 , or 10 minutes,
    and 3 of these had scores of 1 or 2 (i.e., they had severe postnatal
    asphyxia). ... Of the 100 individuals, 58 had one or more remarks in their
    birth- or perinatal records about a serious problem in the peri-/neonatal
    period."

    7.  Cederlund M, Gillberg C.  One hundred males with Asperger syndrome: a
    clinical study of background and associated factors. Dev Med Child Neurol. 2004
    Oct;46(10):652-60.
    For 58 of 99 children, some kind of abnormality was noted in their neonatal
    record. ... Twenty-two had had hyperbilirubinemia (plasma bilirubin more
    than 200μmol/l), ... Hyperbilirubinemia occurs in about 10% of newborn
    infants...  Forty-five of 92 children (49%) for whom fairly detailed data about
    early language development were available, clearly did not have normal
    language development at 2 years of age. It cannot be concluded that the
    remainder had normal language development.

    8.  Glasson EJ et al. Perinatal factors and the development of autism: a population
    study. Arch Gen Psychiatry. 2004 Jun;61(6):618-27.
    "Cases were more likely to have experienced fetal distress during labor
    (OR, 1.64; 95% CI, 1.15-2.34). Apgar scores calculated at 1 minute showed
    that significantly more cases achieved a score of 6 or less (54 [19.5%] of
    277 cases with data recorded since 1991..."
    "[12.9%] of 512 control subjects with data recorded since 1991)(OR, 1.6; 95% CI,
    1.1-2.4), and cases were more likely to have taken more than 1 minute
    before the onset of spontaneous respiration (OR, 1.4; 95% CI, 1.0-1.9)."

    9.  Wilkerson DS et al. Perinatal complications as predictors of infantile autism.  Int
    J Neurosci. 2002 Sep;112(9):1085-98.
    "… 5 items were found to significantly predict group membership
    (prescriptions taken during pregnancy, length of labor, viral infection,
    abnormal presentation at delivery, and low birth weight)."

    10. Hultman CM et al. Perinatal risk factors for infantile autism.   Epidemiology.
    2002 Jul;13(4):417-23.
    "The risk of autism was associated with daily smoking in early pregnancy (OR =
    1.4; CI = 1.1-1.8), maternal birth outside Europe and North America (OR = 3.0; CI =
    1.7-5.2), cesarean delivery (OR = 1.6; CI = 1.1-2.3), being small for gestational
    age (SGA; OR = 2.1; CI = 1.1-3.9), a 5-minute Apgar score below 7 (OR = 3.2,
    CI = 1.2-8.2), and congenital malformations (OR = 1.8, CI = 1.1-3.1)."   Note: The
    OR (odds ratio) was greatest for 5-min Apgar score below 7."

    11.  Zwaigenbaum L et al. Pregnancy and birth complications in autism and liability
    to the broader autism phenotype.  J Am Acad Child Adolesc Psychiatry 2002 May;
    41(5):572-9
    "Children with autism spectrum disorders have lower optimality (higher
    rates of complications) than unaffected siblings…"

    12.  Greenberg DA et al. Excess of twins among affected sibling pairs with autism:
    implications for the etiology of autism.  Am J Hum Genet 2001 Nov;69(5):1062-7
    "In a sample of families selected because each had exactly two affected
    sibs, we observed a remarkably high proportion of affected twin pairs,
    both MZ and DZ…"

    13.  Bodier C et al. Autisme et pathologies associées. Étude clinique de 295 cas de
    troubles envahissants du developpment. [Autism and associated pathologies.
    Clinical study of 295 cases involving development disorders]  Presse Médicale
    2001 Sep 1; 30(24 Pt 1):1199-203. French.
    "Among the children with a serious medical condition, 34.4% also had ante-
    or perinatal antecedents. Among the 33% without any medical factor, 77%
    also had ante- or perinatal antecedents."

    14. Juul-Dam N et al. Prenatal, perinatal, and neonatal factors in autism, pervasive
    developmental disorder-not otherwise specified, and the general population.   
    Pediatrics. 2001 Apr;107(4):E63.
    "… specific complications that carried the highest risk of autism and PDD-
    NOS represented various forms of pathologic processes with no presently
    apparent unifying feature."

    15. Matsuishi T et al. Brief report: incidence of and risk factors for autistic disorder
    in neonatal intensive care unit survivors.   J Autism Dev Disord. 1999 Apr;29(2):
    161-6
    "AD was identified in 18 of the 5,271 children and the incidence was 34 per
    10,000 (0.34%). This value was more than twice the highest prevalence value
    previously reported in Japan. Children with AD had a significantly higher
    history of the meconium aspiration syndrome (p = .0010) than the controls.
    Autistic patients had different risk factors than CP."  Note: CP (cerebral palsy)
    occurred in 57 of the 5,271 children."

    16. Bolton PF et al. Obstetric complications in autism: consequences or causes of
    the condition? J Am Acad Child Adolesc Psychiatry. 1997 Feb;36(2):272-81
    "…[obstetric] optimality score (OS), were compared in two groups: 78 families
    containing an autistic proband (ICD-10 criteria) and 27 families containing a down
    syndrome (DS) proband…  RESULTS: Autistic and DS probands had a
    significantly elevated OS compared with unaffected siblings, regardless of
    birth order position. The elevation was mainly due to an increase in mild as
    opposed to severe obstetric adversities."

    17. Ghaziuddin M et al. Obstetric factors in Asperger syndrome: comparison with
    high-functioning autism.  J Intellect Disabil Res. 1995 Dec;39 ( Pt 6):538-43.
    "Males with AS showed a trend toward lower Apgar scores at one minute
    …"

    18. Lord C et al. Pre- and perinatal factors in high-functioning females and males
    with autism.  J Autism Dev Disord. 1991 Jun;21(2):197-209.
    "These data provide slight support for the contribution of nonspecific pre-
    and perinatal factors to other etiological bases of autism."

    19. Steffenburg S et al. A twin study of autism in Denmark, Finland, Iceland,
    Norway and Sweden.  J Child Psychol Psychiatry. 1989 May;30(3):405-16.
    "In most of the pairs discordant for autism, the autistic twin had more
    perinatal stress."

    20. Levy S et al. A comparison of obstetrical records of autistic and nonautistic
    referrals for psychoeducational evaluations.  J Autism Dev Disord. 1988 Dec;18(4):
    573-81.
    "Abnormal presentation at birth is the only factor that occurred more
    frequently for the autistic sample…"

    21. Lobascher ME et al. Childhood autism: an investigation of aetiological factors in
    twenty-five cases. Br J Psychiatry. 1970 Nov;117(540):525-9.
    "There were more complications of labour in the experimental group than
    the controls (p=0.001) ...Abnormal conditions of the child noted at delivery
    occurred significantly more frequently in the experimental group, e.g.
    difficulty with resuscitation, cord around neck, fractured skull, cyanosis,
    head moulding, bruising, jaundice (p<0.0004)."