Timing of Prenatal Stressors and Autism

D. Q. Beversdorf,1,7
S. E. Manning,2
A. Hillier,1
S. L. Anderson,1
R. E. Nordgren,3
S. E. Walters,4
H. N. Nagaraja,5
W. C. Cooley,3
S. E. Gaelic,3
and M. L. Bauman6

Recent evidence supports a role for genetics in autism, but other findings are difficult to reconcile with a purely genetic cause. Pathological changes in the cerebellum in autism are thought to correspond to an event before 30–32 weeks' gestation. Our purpose was to determine whether there is an increased incidence of stressors in autism before this time period. Surveys regarding incidence and timing of prenatal stressors were distributed to specialised schools and clinics for autism and Down's syndrome, and to mothers of children without neurodevelopmental diagnoses in walk-in clinics. Incidence of stressors during each 4-week block of pregnancy was recorded. Incidence of stressors in the blocks prior to and including the predicted time period (21–32 weeks' gestation) in each group of surveys was compared to the other prenatal blocks. A higher incidence of prenatal stressors was found in autism at 21– 32 weeks' gestation, with a peak at 25–28 weeks. This does support the possibility of prenatal stressors as a potential contributor to autism, with the timing of
stressors consistent with the embryological age suggested by neuroanatomical findings seen in the cerebellum in autism. Future prospective studies would be needed to confirm this finding.

1 Department of Neurology, Ohio State University Medical Center,
Columbus, OH, USA.
2 Dartmouth Medical School, Lebanon, NH, USA.
3 Department of Pediatrics, Dartmouth Hitchcock Medical Center,
Lebanon, NH, USA.
4 Department of Statistics, Ohio State University, Columbus, OH,
USA.
5 Child Health Associates, Ann Arbor, MI, USA.
6 Department of Pediatrics Neurology, Mass General Hospital,
Boston, MA, USA.
7 Correspondence should be addressed to: David Q. Beversdorf,
MD, Means Hall 469, 1654 Upham Drive, The Ohio State
University Department of Neurology, Columbus, OH 43210,
USA; e-mail: beversdorf-1@medctr.osu.edu