Scientists have linked a chemical common in pet shampoos to the development of autism.

As if struggling with pet allergies wasn’t enough already.

University of California at Davis professor Irva Hertz-Picciotto’s research found that women who reported using pet shampoos for fleas and ticks during pregnancy were twice as likely to have children with autism, the Times of London reported.

This supports the view that environmental factors, in addition to genetics, cause autism. Autism is a disorder that can cause severe problems with speech development, difficulties with social interaction, and repetitive behaviour.

In the study, mothers of children with autism were asked to detail any chemicals they were exposed to, from three months prior to conception to their child’s first birthday.

The highest risk of autism was associated with exposure to pet-flea products during the second trimester of pregnancy. Since these products often contain pyrethrins, it’s possible these chemicals could contribute to the development of autism.

Pyrethrins are also found in human head-lice products and indoor bug bombs. In pests, it attacks the central nervous system and has been found to have damaging effects on the brain.

Interestingly, pyrethrins are natural insecticides derived from certain species of the chrysanthemum plant. Who knew?