Prenatal and Early Life Exposure to Stressful Life Events and Risk of Autism Spectrum Disorders: Population-Based Studies in Sweden and England

Academic Unit of Psychiatry, School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom.
PLoS ONE (Impact Factor: 3.23). 06/2012; 7(6):e38893. DOI: 10.1371/journal.pone.0038893
Source: PubMed


Exposure to stressful life events during pregnancy has been suggested as a potential risk factor for offspring Autism Spectrum Disorders (ASD), but the literature is limited and inconsistent. We tested the hypothesis that maternal exposure to stressful life events would be associated with increased risks of offspring ASD, and that these risks would be highest for exposures during the prenatal period.
We used prospectively collected data from two large population based studies in Sweden and England. In the Swedish study of 4429 ASD cases and 43277 controls, our exposure comprised the occurrence of any severe life event before and during pregnancy and the child's early life. In the English study (maximum n = 11554, ASD n = 72), we studied the risk of offspring ASD in relation to a combined maternal exposure to multiple (up to 42) common and rare life events, as well as their perceived impact upon the mother during pregnancy and early life. In crude and adjusted regression analyses in both studies, we found no evidence of an association between prenatal life events, or their number and perceived impact and the risk of offspring ASD. Sub-group analysis of ASD with and without intellectual disability in the Swedish study yielded similar results.
We found no evidence to support the hypotheses that exposure to stressful life events during the prenatal period is associated with an increased risk of offspring ASD.

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Available from: Cecilia Magnusson, Jan 27, 2014
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    • "Another theory posits prenatal maternal stress as a major contributing factor to the development of ASD (Beversdorf et al., 2005; Ward, 1990). However, a recent study by Rai et al. (2012) could demonstrate no explicit relationship between prenatal life events and the risk for developing ASD. It is difficult to resolve these competing theories because prenatal stress is well known to decrease exposure to prenatal testosterone (Ward et al., 2003). "
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    • "As hypothesized, and consistent with some prior literature evidencing that autism spectrum traits (Ronald et al., 2011) and autismprevalence rates (Kinney et al., 2008a) increased with exposure to increasingly severe stress exposure, the current study found both objective hardship and subjective distress were associated with more severe autism-like traits, although most children scored in the subclinical range. Findings are not, however, consistent with two recent population studies (Li et al., 2009; Rai et al., 2012). This discrepancy may be attributable to differences in nature of stress exposure (e.g., sudden-onset of uniform natural disaster versus variable stressors with more diffuse onset). "
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