article_snippet: Chiari malformations are caused by structural defects in the brain and spinal cord.
article_snippet: Chiari malformations mostly occur during fetal development, although Chiari malformations  may develop later in life after injury, infection or exposure to toxic substances .
article_snippet: It was once believed that Chiari malformations occurred in only one in every 1,000 births, but research shows that they appear to be more common.
article_snippet: Babies who are born with Chiari malformations don't develop symptoms until adolescence or adulthood - if Babies who are born with Chiari malformations develop Babies who are born with Chiari malformations at all . '