Season of birth in infantile autism

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“…To begin with, to make our data comparable to the formats used in previous work (Barak et al, 1995;Bartlik, 1981;Bolton et al, 1992;Gillberg, 1990b;Konstantareas et al, 1986;Mouridsen et al, 1994;Tanoue et al, 1980;) a substantial number of tests had to be conducted. Obviously, such a procedure increases the risk of spurious significances, a problem that may have also plagued earlier studies.…”

“…In addition, to enhance uniformity across studies, months were clustered in seasons following the procedure used in a number of previous research reports (e.g., Bartlik, 1981;Bolton et al, 1992;Gillberg, 1990b;Konstantareas et al, 1986). In this seasonal clustering, December, January, and February are referred to as the winter season; March, April, and May as the spring season; June, July, and August as the summer season; and finally September, October, and November as the autumn season.…”

“…Studies that did examine birth patterns of autistic patients relied on samples ranging from 80 to 1,435 (Barak et al, 1995;Bartlik, 1981;Bolton, Pickles, Harrington, Macdonald, & Rutter, 1992;Gillberg, 1990b;Konstantareas, Hauser, Lennox, & Homatidis, 1986;Mouridsen, Nielsen, Rich, & Isager, 1994;Tanoue, Oda, Asano, & Kawashima, 1988). While most of these studies reported deviations in birth patterns of persons who later received a diagnosis of autism, their results are not consistent.…”

“…In their study, the birth pattern of an infantile autistic subsample was found to be the mirror image of that of a subsample of patients with autistic-like disorders (e.g., Asperger syndrome). Similarly, a number of authors have reported that deviations from normal birth patterns are more pronounced in autistic males than in autistic females (Gillberg, 1990b;Konstantareas et al, 1986;Mouridsen et al, 1994). Some studies have focused on the association between intelligence levels of autistic patients and their birth patterns.…”

“…Some studies have focused on the association between intelligence levels of autistic patients and their birth patterns. Studies that have addressed this issue typically find that seasonality of birth is most pronounced among patients with lower IQs (e.g., Konstantareas et al, 1986).…”