Perinatal factors and the development of autism: a population study
Author(s): Glasson EJ, Bower C, Petterson B, de Klerk N, Chaney G, Hallmayer JF
Reference: Arch Gen Psychiatry. 2004 Jun;61(6):618-27
Place of Study: Australia
Abstract: Subjects born in Western Australia between 1980 and 1995 and diagnosed with an autism spectrum disorder by 1999 were included as cases (n = 465). Siblings of the cases (n = 481) and a random population-based control group (n = 1313) were compared with the cases on obstetric information contained in the Maternal and Child Health Research Database of Western Australia. Many negative findings are noticeable. No difference in gestational age at birth (including the proportion of premature infants), weight for gestational age, head circumference, or length were observed between cases and control subjects. Pre-eclampsia did not appear as a risk factor. These negative findings tend to give more importance to perinatal factors. Compared with their siblings, cases were more likely to have been induced (OR, 1.40; 95% CI, 1.03-1.90), experienced fetal distress (OR 1.64), had an Apgar score at 1 minute of 6 or less, and needed longer than 1 minute to breathe spontaneously. Compared with control subjects, cases were more likely to be born after induction (OR 1.43; 95% CI 1.12-1.83), to be born by elective c-section(OR 2.05. P<.001), or to be born by emergency c-section (p .01).