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Cases of autism, which was once thought to be caused by common childhood vaccines, have been on the rise for years. Some people believed vaccines increased a child's risk for autism, causing many parents to decline the use of vaccines for children. However, it's now known that there’s no link between autism and vaccines. But what could be causing the high number of autism cases? The latest autism research suggests some cases of the developmental disorder may be a result of mothers' antidepressant use during pregnancy, although these findings are still preliminary.
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Autism and Antidepressants
A new study suggests that women who use certain antidepressants while pregnant have an increased risk for giving birth to children with autism. Antidepressants that are categorized as selective serotonin reuptake inhibitors (SSRIs) produce a higher rate of autism in unborn children when taken by pregnant mothers. These antidepressants include Prozac, Zoloft, Paxil and similar medications.
When the antidepressants are taken during early pregnancy, they appear to increase the risk for autism. In fact, the study produced evidence that children who are exposed to the antidepressants during the first trimester are four times more likely to develop a form of autism when compared to children who aren’t exposed to the medications. The study consisted of approximately 300 children who were diagnosed with a form of autism. Although the evidence is promising, it doesn’t prove antidepressant use during pregnancy actually causes the condition.
The lead author of the study, Lisa Croen, Ph.D., is also the director of autism research at Kaiser Permanente Northern California. She emphasizes the preliminary findings, "This is the first study of its kind to look at the association, and the findings have to be interpreted with a lot of caution," she says. "We can't detect causality from one study."
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Maternal Mental Health
Larger studies are needed to produce more conclusive evidence. However, the current findings are enough to make women think twice before using antidepressants while pregnant. Unfortunately, even with this evidence and the possibility of increased autism risk, pregnant women will still need to continue the use of the antidepressants. If depression is left untreated during pregnancy, there are risk factors involved, which can include fetal growth complications and preterm delivery.
"Poor maternal mental health during pregnancy is a major public health issue," says Tim Oberlander, M.D., a professor of developmental pediatrics at the University of British Columbia. "Non-treatment is not an option. While some children might be at risk from an SSRI exposure -- and we don't know who, and how that works -- there are many mothers and their children as well who will benefit."
Croen adds, "The potential risks to the child really have to be balanced with the risk to the untreated mom. We don't want people to rush off and stop taking antidepressants if they're on them. They really need to talk to their doctors about the risk-benefit ratio."
The link between antidepressant use and autism doesn’t end with just use during pregnancy. The study also showed women who used the antidepressants one year prior to conceiving also had a higher risk for giving birth to an autistic child. Results showed women who use antidepressants before pregnancy are at least twice as likely to have a child with autism.
With this latest autism research, some women may become concerned with the use of antidepressants during pregnancy, but the study conductors report, "the fraction of cases of ASD (autism spectrum disorders) 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."
Further evaluations of antidepressants and autism are still needed because the current findings could have only occurred by chance, and there may be many more plausible explanations for the high number of autism cases. Pregnant women shouldn’t stop using antidepressants just because there appears to be a modest link between antidepressants and autism.
"As a general practice, I believe most [primary care physicians] discourage women considering pregnancy to avoid using medications that are not necessary, but the benefits of SSRIs in treating depression and as alternatives to other measures have to be weighed on an individual basis," said Catherine Lord, director of the University of Michigan Autism and Communication Disorders Center in Ann Arbor.
Until further studies are conducted, pregnant women should continue the use of their antidepressants. Should the results become conclusive, an individual’s risk for an autistic child and the side effects of ceasing the use of the medication will need to be evaluated to determine the appropriate course of action.
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"Are antidepressants linked to autism?" http://abcnews.go.com/Health/Autism/autism-antidepressants-environmental-factors/story?id=14037214
"Antidepressant use in pregnancy can raise autism risk" http://www.cnn.com/2011/HEALTH/07/04/antidepressant.pregnancy.autism.risk/index.html