July 5, 2011
Autism Risk Increased With Antidepressant Use By Mothers
Pregnant women who took anti-depressants during pregnancy were found to be twice as likely to have a child diagnosed with autism or a similar disorder, according to a new study appearing in the Archives of General Psychiatry.
Zoloft, Prozac, and similar anti-depressants, known as selective serotonin reuptake inhibitors (SSRIs), may be especially risky early on in a pregnancy, the study suggests. Children who were exposed to the drugs during the first trimester were nearly four times as likely to develop an autism spectrum disorder (ASD) compared with unexposed children.
In the general population, researchers explained, "the fraction of cases of ASD that may be attributed to use of antidepressants by the mother during pregnancy is less than 3 percent...and it is reasonable to conclude that prenatal SSRI exposure is very unlikely to be a major risk factor for ASD."
These results could also be due to chance since there were only 20 women in the study who took SSRIs and had a child with ASD.
The study is a "signal, but with a really small group," explains Max Wiznitzer, M.D, pediatric neurologist at Rainbow Babies & Children's Hospital and an associate professor of pediatric neurology at Case Western Reserve University School of Medicine, both in Cleveland.
Using Kaiser Permanente's patient database, researchers identified 298 children with an ASD who were born between 1995 and mid-1999, and matched them with 1,507 children without autism who were roughly the same age and were born in the same hospitals.
The authors then cross-checked whether their mothers, in the year before delivery, filled prescriptions for an SSRI, including Prozac, Zoloft, Luvox, Celexa, and Paxil (or their generic versions). The researchers could not confirm whether the mothers actually took the medication, however.
Twenty of the children with an ASD (or 6.7 percent) were exposed to SSRIs in the womb, compared with 50 (3.3 percent) of the control children.
Taking into account other factors that could affect both autism risk and SSRI use (such as the mother's age, ethnicity, and history of depression or other mental illness), the researchers found that any exposure to the drugs in the womb increased the risk of ASD diagnosis 2.2-fold, while first-trimester exposure increased the risk 3.8-fold.
The Food and Drug Administration (FDA) has assigned most SSRIs a "C" grade for safety during pregnancy. Drugs given at high doses in this category have been linked with birth defects in animal studies, but they have not been proved safe or unsafe in humans due to the small number of studies.
Pregnant women should use them "only if the potential benefit justifies the potential risk to the fetus," according to the FDA.
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