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Autism Risk Increases in Closer-Born Siblings

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Autism related image Photo: Getty Images

In my family, I am the youngest of three siblings. The total number of months separating my oldest brother and me is a mere 34. Bless my mom’s heart, as I’m sure having three kids within three years was not a simple task.

My mom and dad placed value on and thought it was important to have children close together in age. And because of it, my brothers and I were close growing up. We played on the same sports teams, helped each other with homework and always challenged and motivated one another.

Now, as adults, we remain extremely close-knit and are always there for one another. I couldn’t be more grateful to have brothers so close to me in age. But what neither my parents nor researchers knew back in the 80s when we were all born is that having children so close together increases the risk of autism in the younger babies.

As USA Today’s Liz Szabo reported, a study published in a recent issue of Pediatrics found that “children who were born less than one year after an older sibling were more than three times as likely to be diagnosed with autism, compared with children born at least three years after their mother's last pregnancy. Children born less than two years after an older brother or sister were almost twice as likely to be diagnosed with autism.”

The new study was conducted between 1992 and 2002 and involved more than 660,000 children born during that time. Researchers said this study provides more evidence that autism is related to events that happen early in pregnancy.

“Autism is a complex developmental disability that typically appears during the first three years of life and affects a person’s ability to communicate and interact with others,” according to the Autism Society website.

“Autism is defined by a certain set of behaviors and is a ‘spectrum disorder’ that affects individuals differently and to varying degrees. There is no known single cause for autism.”

Doctors and researchers believe that one reason autism becomes more likely in later-born children is that pregnancy depletes mothers of vital nutrients such as iron and folic acid. Without long periods in between pregnancies, women may not be able to build up a large enough supply of such nutrients to then be able to pass on to later-born babies.

Closely spaced pregnancies also have been found to increase the risk of schizophrenia, premature birth, low birth weight and other conditions, according to the study’s co-author, Peter Bearman.

While the exact number of children with autism is not known, the U.S. Center for Disease Control and Prevention suggested that autism is on the rise. Some have said that autism rates today are at least 10 times higher than a couple decades ago, but researchers stress that the spike in autism may simply be due to the way we define, diagnose and report on the illness. For example, a child who is diagnosed with high-functioning autism today may have been thought to simply be odd or strange 30 years ago.

Autism Society

Autism—Google Health

Autism risk rises in babies born soon after sibling

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We value and respect our HERWriters' experiences, but everyone is different. Many of our writers are speaking from personal experience, and what's worked for them may not work for you. Their articles are not a substitute for medical advice, although we hope you can gain knowledge from their insight.


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