Autism spectrum disorder (ASD) and SSRI antidepressants may have a link in pregnancy, according to multiple studies, but disagreement over research results continues. The public remains largely unaware of the study findings, not to mention the controversy.
Selective serotonin reuptake inhibitors, or SSRIs, include such medications as Prozac, Celexa, Paxil and Effexor. Multiple studies since 2011 have looked at the connection between women who are prescribed SSRIs and children born with autism.
One in 50 school-aged children in the United States is diagnosed with autism. Seven to 13 percent of all pregnant women take antidepressants.
A 2011 study from Kaiser Permanente documented that the risk of having a child born with ASD doubled while taking antidepressants during pregnancy. The risk quadrupled with antidepressant use in the first trimester. The study also looked at depressed women who were not on SSRIs during pregnancy, and found no increased risk of autism.
The Kaiser study conclusions were discounted because they were the first human studies of the autism-antidepressant correlation, and only included 300 children with ASD. Other researchers and physicians have leaned toward encouraging pregnant women to keep taking their medications, saying more studies are needed to confirm the Kaiser findings. They express concern about the potential risk to the child from an untreated mother.
A larger study from Sweden was released in 2013 with similar results. In the Swedish study, mothers of children with autism were found to be over three times more likely to have taken antidepressants while pregnant. This report concluded that prenatal exposure to either SSRIs or tricyclic antidepressants was associated with an increased risk of ASD.
A Danish study released in November 2013 was the largest study yet. This study concluded that findings of risk were insignificant based on the small number of children who had both autism and antidepressant exposure, which was only 52 out of 600,000. But the researchers did acknowledge that it was not possible to rule out small increase in risk.
There is some disagreement with the Denmark study conclusions, as there is no significant correlation between autism and antidepressant use. First, the rate of antidepressant use during pregnancy is very low in Denmark. Also, the study authors said their results were not statistically significant because they did not prove with 95 percent certainty that an association exists, although they do acknowledge that the findings do not disprove the connection.
Both the Swedish and Danish studies question whether the rise in the risk of autism is related to antidepressant use or depression itself.
Late in 2013, a new study from Norway was published in the Journal of Clinical Epidemiology. This study looked simply at the question of whether women who are prescribed SSRIs prior to pregnancy actually continued to take them once they became pregnant. Many of the previous studies work off the theory that pregnant women do continue taking their antidepressants.
The Norway researchers showed that many of the women in their study did not continue taking their antidepressants once they became pregnant. Studies that include these women as users make for a smaller percentage of results showing a connection, with the results showing the risk seems smaller.
Scientists say the developing fetus has millions of serotonin receptors, and they need serotonin for proper brain development. Since SSRIs inhibit serotonin, the conclusion of some experts is that interfering with serotonin can affect brain development in the fetus.
In December 2013, Autism Speaks said the studies show a possible connection, but advise using caution before rushing to judgment. The group acknowledges the disagreement in the findings, saying the studies were small but show a correlation in antidepressant use and autism, though the increase in risk found was modest.
By Beth A. Balen