COLUMBIA, Mo., May 16 -- Prenatal exposure to thimerosal in Rh immunoglobulin (RhIg) does not increase a child's risk for an autism spectrum disorder, said investigators here.
Compared with women in the general population, mothers of children with autism were no more likely to be Rh negative, to have received RhIg preserved with thimerosal during pregnancy, or to have had pregnancies complicated by Rh incompatibility, reported Judith Miles, M.D., Ph.D., and Nicole Takahashi, online in the American Journal of Medical Genetics.
"This study adds to the evidence that there is no casual association between thimerosal and childhood autism," said Dr. Miles, a professor of pediatrics and pathology at the University of Missouri, who also holds an endowed chair in autism. "We conclude that there is no indication that pregnancies resulting in children with autism were more likely to be complicated by Rh immune globulin/thimerosal exposure."
Thimerosal, which is 49.6% ethylmercury, was included as a preservative in RhIg and in pediatric vaccines manufactured in the United States until 2001.