Here is what little information I was able to find about breastfeeding and
autism when writing my new book:

"Another 'terrain of ignorance' is the degree to which premature weaning (or
not being breastfed at all) contributes to such clinical entities as
attention deficit disorder, attention deficit hyperactivity disorder,
autism/pervasive developmental disorder, and other cognitive/behavioral
disorders in children.  Does bottle-feeding contribute to the etiology of
these conditions, or make the symptoms more severe?  To phrase it the other
way, does breastfeeding (or extended breastfeeding) reduce the risk of these
conditions and/or lessen the severity of symptoms?  Two anecdotal reports by
mothers suggest that autistic children who had been breastfed for many years
are more open to physical contact with other people.  However, a search of
the medical literature back to 1966 revealed only two studies of
autism/pervasive developmental disorder (PDD) that included infant feeding
as a variable (Burd et al., 1988; Tanoue and Oda, 1989).
        Burd et al. (1988) looked at breastfeeding rates among children with PDD,
matched controls, and their older and younger siblings, to see if PDD
affected frequency or duration of breastfeeding in the cases or their
siblings.  Tanoue and Oda (1989) found that their controls had longer
durations of breastfeeding than their cases (children who developed autism),
even though the children in their sample were only breastfed for a very
short time.  They suggest that since pneumonia in early infancy is a known
precipitating factor for autism, and since breastfeeding protects against
pneumonia, this may be the mechanism through which breastfeeding lowers the
risk of developing autism.  No studies have looked at the severity of
autistic symptoms based on duration of breastfeeding.  In particular, no
studies have looked at cases of autism thought to be of prenatal origin (due
to mother's illness during pregnancy) and later cognitive and behavioral
outcomes based on duration of breastfeeding."


Burd, L., Fisher, W., Kerbeshian, J., Vesely, B., Durgin, B. and Reep, P.
(1988)  A comparison of breastfeeding rates among children with pervasive
developmental disorder, and controls.  Developmental and Behavioral
Pediatrics 9, 247-251.

Katherine A. Dettwyler, Ph.D.
Associate Professor of Anthropology and Nutrition
Texas A&M University