OBJECTIVE: Variations in month of birth were examined in patients with
infantile autism to test the hypothesis that birth in a particular month
may be a risk factor for this disorder. METHOD: Data for autistic patients
registered with the National League for Autism in Israel (N = 188) during
the years 1964-1986 were compared with data on monthly distribution of live
births in Israel for the corresponding period. RESULTS: After risk ratio
estimates were computed for children born with infantile autism for each
month, a significant increase was observed for children born in March and
August. This association was true for each year throughout the study. An
additional finding was a significantly higher rate of birth of autistic
children in the years 1970-1976. CONCLUSIONS: This study, although made in
a different climatic area than three earlier studies, further emphasizes
the earlier findings that March and August births are a risk factor for
development of autistic disorder.Abstract Teaser