It is common knowledge: As women get older, pregnancy becomes a riskier enterprise. Advanced maternal age is linked to a number of developmental disorders in children, such as Down's syndrome. Now, a study has confirmed that older mothers are more likely to give birth to a child with autism, too.

The authors of the epidemiological study, published February 8 in Autism Research, examined the parental age of more than 12,000 children with autism and nearly five million "control" children between 1990 and 1999, all living in California. The researchers found that mothers over 40 had a 51 percent higher risk of having a child with autism than mothers 25 to 29, and a 77 percent higher risk than mothers under 25.

Autism—a developmental disorder characterized by impaired social interaction and communication—appears to be on the rise. The U.S. Centers for Disease Control and Prevention now estimates that as many as one in 110 children in the U.S. has an autistic spectrum disorder—a group of developmental disorders including autism, Asperger's syndrome and pervasive developmental disorder. The prevalence of autistic spectrum disorders in California in 2007 was 12 times that from 1987, representing an average annual growth of 13 percent, according to a report from the California Department of Developmental Services. Only a fraction of these extra cases can be explained by changes to diagnostic criteria and earlier diagnoses.

Maternal age is also increasing in the U.S. A California-based study reported a three-fold increase in the number of births to women aged 40 to 44 between 1982 and 2004. But this trend toward delayed childbearing accounted for less than 5 percent of the total increase in autism diagnoses in California over the decade, according to the study—a finding that surprised Janie Shelton, a doctoral student in University of California, Davis's Department of Public Health Sciences and the study's lead author. "I would have expected to see more of a contribution, because age is a risk factor and women are having kids later," she says.

Earlier work had suggested that both maternal and paternal ages are independently associated with autism risk. But the current study found that paternal age is only a risk factor when the mother is under 30. It follows similar results obtained from the same California sample, published in September 2009 in the American Journal of Public Health, which showed that pooling data artificially inflates the risk of paternal age, and that advanced maternal age likely poses the greater risk. "It's nice to see replication of prior work," says Peter Bearman, co-author of the 2009 paper. Neither research team investigated whether increasing maternal age worsened autistic symptoms, although a 2007 study published in the Journal of Autism and Development Disorders that measured autistic children's cognitive and social function failed to make that link.

Mothers over 35 are at a higher risk for prolonged labor, premature or breeched deliveries, and birth to babies with low Apgar scores (a rating index used to evaluate the condition of a newborn infant)—all factors that have been associated with autism. But they might also be more likely to seek diagnoses to explain their child's abnormal behavior. "That's definitely an important thought, and I think that there is some evidence to suggest that people with higher education and higher socioeconomic status in general are more adept at navigating the diagnostic process here in California," Shelton says. "[Parents] need to be motivated to get the diagnostic and treatment services that are granted to them by the state. There are certain cases we're missing because the parents don't know about the services that are available or they haven't worked out how to navigate the system yet." The proportion of parents of autistic children with fewer than 24 years of combined education in the study was smaller than that of "control" birth parents, (19 percent and 36 percent, respectively).

13 Comments

1. 1. Telrunya 04:00 PM 2/11/10

   Interesting corralations. My wife was 22 when she had our son who is autistic and I was 30. Then again we had two more children after him who aren't autistic. I remain convinced that MMR played a role in the onset of our son's autistic symptoms. I'm sure genetics play a strong role in making someone predisposed to autism but environmental factors are the trigger. All three of our children displayed developmental delays, but our oldest is the only one we had innoculated with the MMR shots at 2 years old. We waited for the other 2 until they were 4 years old. Immediately after being innoculated our oldest son got sick and withdrawn from his usually engaging personality. He got over the cold realitively quickly but remained very withdrawn. I'm not against vaccinations but firmly believe that 2 years old, when they are still very much developing mentally, is WAY too early and can be the trigger that activates a latent predisposion towards autistic tendancies

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2. 2. fisixisfun 12:40 AM 2/12/10

   I'm sorry your son has autism, but from what I understand there has never been any link established between MMR and autism. The article that spawned that idea was based on a study of 12 kids, 10 of whom had autism, that was looking for measles viruses in their intestines, presumably something to do with bowel conditions. The research was then discredited by other researchers after it had been published, and the man who did the research either resigned or was fired (I forget which) from his position in the UK, and moved to the US, where he began selling the idea that vaccines cause autism.

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3. 3. Lone Wolf 83 12:47 AM 2/12/10

   Vaccines do not cause autism. There have been many studies done and only one has shown a link and even if you ignore all the unethical things the lead author (Andrew Wakefield) did, the study was poorly done and has only 12 subjects and even if you ignore that it was only one study. Many more studies have been done sense and they all show no correlation between autism and vaccines.
   All this "MMR causes autism!" crap has only caused children to not get vaccinated and weaken herd immunity, which has caused children to catch vaccine-preventable diseases and many have died from them. Allot of money has been spent of researching this supposed link between vaccine and autism when that money could have been spent on researching causes and treatments for autism.
   I'm not going to pretend to know what your going through. I know its highly emotional. There is no connection. You and other who believe in this connection need to accept that there is no connection. I know people like to have things to blame when bad things happen but right now there is nothing to blame and in the end it may just be the luck of the draw.

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4. 4. LarianLeQuella 10:49 AM 2/12/10

   http://factsnotfantasy.com/vaccines.html - That link should directly address the LIES and distortions told by the anti-vax pro-disease nutters.

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5. 5. Rhettfairy in reply to Telrunya 02:33 PM 2/12/10

   Telrunya,
   
   Can you please explain why you firmly believe this? I'm willing to give you the benefit of the doubt that maybe you have new information that the rest of us don't have. What evidence do you have that goes against all of the research of the last decade and beyond that leads you to believe that MMR triggers autism? And what is the mechanism? Any information would be greatly appreciated.

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6. 6. Darpanpadaria 11:23 AM 2/17/10

   I think there must be solution of this thing like taking perfect food which is necessary for brain in developing stage like almond, turkey, etc. in which there are higher level of tryptophen amino acide.

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7. 7. Darpanpadaria 12:55 AM 2/18/10

   If Pregnant lady know how to program brain she can prevent her child form autism. (I think so)

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8. 8. lamorpa in reply to Telrunya 05:21 PM 6/14/10

   @Telrunya: Your 'study' had only 3 participants and no control group - translation, you're using anecdotal evidence (def.:evidence, which may itself be true and verifiable, used to deduce a conclusion which does not follow from it, usually by generalizing from an insufficient amount of evidence.) Sorry for your difficulties. Please don't encourage other parents to skip or delay vaccines, because they will be putting their children and those around them at increased risk from dangerous and fatal diseases.

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9. 9. asheffield7 08:58 PM 9/22/10

   Vaccines do not lead to autism. Earlier this year, the scientist who originally claimed that statement withdrew it, saying that it was published without the correct evidence to prove it. Besides, children are born with autism, they don't just develop it because of something bad they ate. Autism is much like a child born without fingers or their heart on the outside of their chest. Something during development simply happens and due to the sudden surge of it in recent years, there is something acting as a catalyst, but it is not vaccines. I personally do not have an autistic child, nor any children at this time, but have become very close to a neighbor's child who suffers from severe autism, so I know what this disorder entails. The article states that there is a link between older mothers and autistic children and that can honestly be looked at as a possible claim, but the fact of the matter is, a lot is still unknown about this disorder and it will take time to come up with any solid evidence to prove anything.

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10. 10. robertK 11:35 PM 1/11/11

    If we can still remember, Andrew Wakefield created a firestorm when he published a childhood autism study in 1998 implicating vaccines. Wakefield's study has been utilized by anti-vaccination advocates such as Jenny McCarthy of MTV fame to further their cause. The proof is here: <a title="Andrew Wakefield labeled a fraud for linking vaccines to autism" href="http://personalmoneystore.com/moneyblog/2011/01/06/andrew-wakefield-fraud-autism/">Andrew Wakefield draws more fire for bogus autism/vaccine study</a>. Wakefield’s claims could hardly withstand scientific scrutiny, which lead to his ouster from the profession of medicine and most recently, public indictment of frauds. He will definitely be trying to find personal loans to get legal advice if accusations of fraud are to continue.
    
    

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11. 11. guppy24 05:16 PM 3/22/11

    How long will it take people to understand that autism - or most autistic traits- are most likely caused by using pitocin at birth? Children are born with a lack of oxygen to the brain. After birth, the babies are deprived of being held, and this causes furture failure to thrive. It is a mixture of western birth practices in combination with normative abuse. This is why autism rates are much lower in cultures where co-sleeping and natural births are prevalent.

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12. 12. reishi9154 07:07 PM 10/21/11

    So, if I am reading this right, you can't have kids under 30 and you can't have them over 40? That leaves a relatively small window of time. This may be one of the factors, but I believe there are a whole lot of factors that go into autism causation, and it may turn out that this isn't one of the bigger ones.
    More time and studies are needed.
    I have Asperger's, and my mom was 31 or 32 when she had me. My dad was 4 years older. So in my case at least age was not a risk factor.
    If anyone wants to learn more about Asperger's, a good site to go to is http://aspergerssociety.org/articles/toc.htm
    
    I hope the scientific research keeps up so we can answer this question eventually.

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13. 13. Bluevariable 08:49 PM 12/9/11

    All those whose kids are autistic should make this research done by Dr. Natasha Campbell-McBride by mandatory reading. This site below has some information for interested parents.
    http://articles.mercola.com/sites/articles/archive/2011/07/31/dr-natasha-campbell-mcbride-on-gaps-nutritional-program.aspx
    
    I sent this info to a friend whose kid is autistic and he followed her guidance and claims he has seen remarkable results and a transformation in his child's personality. At the very least her points make good sense and merit serious investion and consideration.
    

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