Antidepressants during pregnancy may increase autism risk: study

Women who take antidepressants during pregnancy may be at a higher risk of having children with autism, said a study published Monday by the U.S. journal JAMA Pediatrics.

"The variety of causes of autism remain unclear, but studies have shown that both genetics and environment can play a role," said Professor Anick Berard of the University of Montreal, who led the Canadian study of nearly 150,000 pregnancies.

According to her, taking antidepressants during the second or third trimester of pregnancy almost doubles the risk that the child will be diagnosed with autism by age seven, especially if the mother takes selective serotonin reuptake inhibitors, often known by its acronym SSRIs.

Berard and her colleagues used data on all pregnancies and children in Quebec, Canada's largest province, between January 1998 and December 2009.

Of the 145,456 full-term singleton infants born alive, 1,054 were diagnosed with autism, on average at 4.5 years of age. The children were followed up for an average of 6.2 years.

The researchers identified 4,724 infants who were exposed to antidepressants in utero; 4,200 infants were exposed during the first trimester and 2,532 infants were exposed during the second and third trimester, a period critical to a fetus's brain development.

There were 32 infants exposed to antidepressants during the second and third trimester diagnosed with autism and 40 infants exposed during the first trimester diagnosed with autism, according to the results.

After adjustment for all potential confounders such as genetics and maternal age, the use of antidepressants during the second or third trimester was associated with an 87 percent increased of autism, while no association was observed between the use of antidepressants during the first trimester or the year before pregnancy and the risk of autism.

The results indicated the increased risk of autism was observed with selective serotonin reuptake inhibitors and with the use of more than one class of antidepressant during the second and third trimester.

"It is biologically plausible that antidepressants are causing autism if used at the time of brain development in the womb, as serotonin is involved in numerous pre- and postnatal developmental processes, including cell division, the migration of neuros, cell differentiation and synaptogenesis -- the creation of links between brain cells," Berard explained.

"Some classes of anti-depressants work by inhibiting serotonin (SSRIs and some other antidepressant classes), which will have a negative impact on the ability of the brain to fully develop and adapt in-utero," she said.

The findings are hugely important as six to ten percent of pregnant women are currently being treated for depression with antidepressants and the World Health Organization indicated that depression will be the second leading cause of death by 2020, which led the researchers to believe that antidepressants will likely to remain widely prescribed, including during pregnancy.

"Our work contributes to a better understanding of the long-term neurodevelopmental effects of anti-depressants on children when they are used during gestation. Uncovering the outcomes of these drugs is a public health priority, given their widespread use," Berard added. Endite