Autism spectrum disorder (ASD), more commonly known as autism, is a mystifying diagnosis that leaves heartbroken parents and a puzzled medical community wondering what happened, when and why. A significant degree of focus has been on a mother’s mental health during pregnancy and the medications she may take to alleviate symptoms of mental or emotional distress. A new study suggests it isn’t how she’s feeling or what she’s taking during pregnancy that is cause for alarm. It could be about what happens even before she becomes pregnant.

Selective serotonin reuptake inhibitors (SSRIs) are a class of medications often prescribed for anxiety and depression, even during pregnancy. The concern has been that these prescription drugs taken during pregnancy may increase the risk that the child the woman carries will develop autism.

A team of researchers at the Statens Serum Institute in Copenhagen, Denmark, has found the risk for autism development is actually greater when a woman takes SSRIs before pregnancy. This class of drug is prescribed for a specific set of symptoms and the research suggests it’s these symptoms and therefore the medical condition they describe that contributes to the risk of autism in their offspring, not the drugs they take to treat the condition.

Denmark maintains a national registry of prescription drugs as well as vital statistics such as birth records. The research team mined these databases to find 626,875 women who had babies in Denmark between 1996 and 2005. Of them, 3,892 had children later diagnosed as autistic.

Of these mothers giving birth to autistic children, 52 had been prescribed SSRI antidepressants during pregnancy. The SSRIs included Paxil, Prozac, and Zoloft.

The risk of autism in the offspring was 20 percent higher when mothers took antidepressants during pregnancy. This slightly increased risk was determined to be too small to be statistically significant.

Further study, of women who took prescription antidepressants before pregnancy, revealed a much higher risk - 46 percent - of autistic offspring, even when mothers stopped taking the SSRIs months before getting pregnant. This increased risk of autism is not considered coincidental and represents a significant link between pre-pregnancy SSRI use and the risk of children developing the autism spectrum disorder.

The increased risk of autism suggests the mother’s pre-existing mental health diagnosis may be more revealing than the medications she takes to treat the disorder. Her underlying psychiatric disorder itself may influence autism development rather than how her disorder is treated.

The findings of a study published in 2012 explored possible links to autism when a parent or sibling of the autistic child was schizophrenic. The increased risk of autism was about three times higher when schizophrenia runs in the family.

When the findings of the two studies are examined together, the link between family history of psychiatric disorders and autism is strengthened.

Source:  Hvlid, Anders, et al. “Use of Selective Serotonin Reuptake Inhibitors during Pregnancy and Risk of Autism (preview).” The New England Journal of Medicine. Massachusetts Medical Society. Dec. 18, 2013. Web. Dec 23, 2013.