Closely spaced pregnancies increase autism risk
January 10th, 2011
12:01 AM ET

Closely spaced pregnancies increase autism risk

The likelihood that a child develops autism may be tied to how close together a mother spaces the births of her children, according to research in the journal Pediatrics. The new study found that children conceived before their older sibling was a year old were three times more likely to be diagnosed with autism than children spaced at least three years apart.

"This is an intriguing finding, it potentially points to another one of the risk factors for autism," says Andy Shih, Ph.D., vice president of scientific affairs for the organization Autism Speaks.

The researchers looked at more than 660,000 second-born children in California between 1992 and 2002. Even after adjusting for factors such as a mother's age, race and education levels the findings still held.

What seems to be driving this increase? Study author Keely Cheslack-Postava, Ph.D., from Columbia University in New York says that she and her fellow researchers did not investigate this specifically, but they suspect mothers may not have had enough time between pregnancies to build up the much needed nutrient reserves of folate and iron, important to a developing fetus.

Another theory is that autism is detected and diagnosed more easily when siblings are close in age and developmental differences are more recognizable.

The consensus among autism experts is that the disorder is most likely caused by a combination of genetic and environmental risk factors. According to  Shih,  scientists have made great strides in the quest to understand the genetics of autism, but research on environmental triggers is lagging behind.

"What this paper points out and confirms and something the research community has long suspected from other studies, is that prenatal environmental factors are also important in a child's development [of autism]," says Shih.

Researchers say until other studies confirms these findings it's premature to recommend that parents make changes in the length of time between pregnancies in hopes of reducing the risk of autism.

"Awareness of risk factors is important, but the most important thing a parent can do if concerned about their child's development is see a doctor. Don't wait, because the earlier the detection [of autism] the better the prognosis might be," explains Shih.

soundoff (173 Responses)
  1. Adam

    Isn't it weird they don't say who funded the study? Research before showed that it was a newborn's vaccinations that caused it. Would you really put it past a pharmaceutical company to try and find any possible cause other than their product? Whoever believes this needs to think twice about what they read.

    January 10, 2011 at 13:05 | Report abuse | Reply
    • Doug

      Good try, but this was funded by the Robert Wood Johnson Foundation and the NIH (not pharmaceutical companies). CNN almost never mentions funding sources, but if you are interested, you can almost always find them at the end of the actual research article.

      January 10, 2011 at 14:00 | Report abuse |
  2. Rocksor

    Correlation does not equal causation.

    This particular study doesn't say much.

    January 10, 2011 at 13:11 | Report abuse | Reply
  3. Rose Deats

    Unfortunately, there are a lot of things that cause diseases including environment, diet, nutrition, genetics, etc... The idea behind research is to try to find causative links to diseases. If the data support the correlation between the supposed effect and the disease, then it should not be overlooked (no matter how absurb it may appear). Having babies too close to each other could not be great for either the mother or the child. This may be one of the factors, but obviously not the whole picture. Women in the early part of the 20th century had more babies and gave birth with a higher frequency than we now do, so why are we seeing so many more autistic children these days?

    January 10, 2011 at 13:18 | Report abuse | Reply
  4. Jorma J. Takala

    christen You really need studies to tell you formaldehyde and sodium cyanide are what?

    Safe for you?


    You aren't intelligent enough to know formaldehyde and sodium cyanide and petroleum based coal tar are not safe?

    You don't have at the least, That much faith in your own ability to think this on your own?

    You think I am the only one?

    January 10, 2011 at 13:37 | Report abuse | Reply
  5. MommyS

    I actually have considered this possibility myself. We have participated in a research study for families where one child is on the spectrum and the other isn't. My second son is on the spectrum, and the first isn't. Both children have the same parents, I received the same medical care, ate the same way, lived in the same place, etc. But one thing that did stand out was that the second child was conceived just 7 weeks after the first was born (not intentionally!).

    While it's not THE thing that "causes" Autism, I certainly think it could be one thing that may contribute to it.

    January 10, 2011 at 14:04 | Report abuse | Reply
  6. Linda

    Since no one has defined answers to Autism. Let's see what we, ordinary folks, can do to help besides donating $ to further research on this subject. One can help the parents who have Autistic child (or children) with phsical help, i.e. offer baby sitting to let the parents have a night off, cook some meals for the parents. Anything that can help the parents some slack time, etc. My younger daughter and her husband used to cook a good meal and brought it over to their friends who have two boys with autism, and played with the boys, so the parents could have a meal without interruptions. They also babysitted the boys so the parents could go out for a movie. Now that they have moved away to another state, every chance they got back, they'd visit the boys and play with them to let the parents off the task of taking care the children for a little while. You can do that for your friends, relatives if they have child (or children) with Autism. One can't save the world, but one can help the one you know.

    January 10, 2011 at 14:15 | Report abuse | Reply
  7. Jorma J. Takala

    Please remove my previous postings, I don't think anyone deserves to know my story!

    January 10, 2011 at 14:24 | Report abuse | Reply
    • notmyrealname

      Ahahhahhaha! No one deserves to suffer from having to read your drivel, you mean.

      January 10, 2011 at 17:36 | Report abuse |
  8. Dee

    Both of my children are autistic. Both were born in that time frame from the study. One in 1994 the other in 1996. They were 22 months apart. My first child, less effected, was given her Hep. B shot one month after birth. My second child was given this shot at birth. Do I blame vaccines? Maybe? Do I think vaccinations are necessary? Yes. Do we have certain dog breeds that can't take certain vaccines? Yes. Do I think it is possible genetics has a role in how our body metabolizes all the crap we put into it? YES!!! Let's spend the money on treatments & assistance for families!

    January 10, 2011 at 14:24 | Report abuse | Reply
  9. R. L. Cima, Ph.D.

    Yet another "study" that impacts these very special kids and their trusting parents.  While I don't deny the numbers – I'm sure they are accurate – the spin is nonsense – a pregnancy and autism "link" – and points to the exuberance of the diagnosers and researchers, not these kids or their families. From 1 in 10,000 to 1 in 100 in less than 20 years. Only ADHD rivals this "epidemic," and for the same reasons.  This "diagnosis du jour" has lasted nearly two decades and has become a cottage industry.  Experts are everywhere.   

    There's a more cogent conclusion that can be drawn from the data collected by the California Department of Developmental Services:  autism diagnoses increase as diagnosers become "aware" of these "symptoms."  In addition to ADHD, this occurred with "multiple personalities" 50 years ago, "bi-polar" disorder now, and dozens of others.  Despite the enormous odds, families with multiple autistic children are common, as "symptoms" are seen by anyone who reads an article or attends a lecture.    

    Bless their parents.  They gave sought help for their otherwise healthy children from misinformed and zealous therapists, social workers and, God help them, psychiatrists in the past ten years as this population has grown geometrically.

    No, there's no connection or "link" in this study, other than the linkage speculated by the studiers, anymore than the "link" to vaccines that was recently exposed as fraud – not "mistaken," not "misinterpreted" – fraud.  

    Autism, to a growing number of professionals – as it was before the "epidemic" – is neither a disease nor a disorder.  These young, budding artists and performers need avenues to express their unique talents, and patient adults to guide and encourage them, and many parents know this. 

    Keep them away from the doctors and other professionals who yearn to fix them.  And keep them from well-meaning researchers bent on finding evidence for their preconceived conclusions.       

    January 10, 2011 at 14:37 | Report abuse | Reply
    • Jorma J. Takala

      better yet..... stop giving them artificial colors made from petroleum based coal tar and stop giving them EDTA which is made from formaldehyde and cyanide.

      Do you need millions spent on another study to tell you that cyanide is a deadly poison? That formaldehyde is embalming fluid?

      That anything made from poison is what??

      anyone? anyone?
      Bueller? Bueller? ......POISON?

      EDTA is deadly and I don't need someone else to tell me that it is deadly. I'm just not that stupid.

      Go 100% organic and you will see your autistic child wake up from the same chemically induced walking coma that I suffered throughout my entire life.

      I am Autism!

      January 10, 2011 at 15:45 | Report abuse |
  10. horse_dudu

    This is just complete bs. This study is so flawed. It's taking attention away from what really causes autism: underlying mitochondrial dysfunction triggered by a complete assault on the immune system with vaccines. I bet MERK funded this. People have been having 5-10 kids since the dinosaurs and no was was autistic until they introduced all this modern crap. I'm not Amish, I love western medicine but no one is investigating the non specific effects of vaccines or the side effects of essentially sterilizing our immune systems. go here for some eye opening stuff: the WHO (World Health Organization had discovered non specific effects associated ith the MMR vaccine in girls but refuses to publicize the study). http://www.bmj.com/content/321/7274/1423.extract

    January 10, 2011 at 15:01 | Report abuse | Reply
  11. Sue

    Before birth control was developed and accepted, many families had children close together – yet the autism rate is skyrocketing NOW. Why aren't we investigating pesticides on lawns for fear of a dandelion? Additives in foods?

    January 10, 2011 at 15:23 | Report abuse | Reply
    • notmyrealname

      No, the autism rate is NOT "skyrocketing now." There are more children being DIAGNOSED now because there's an increased awareness of autism and the spectrum disorders. There have always been autistic children, and there are probably the same percentages now as there have always been.

      January 10, 2011 at 19:48 | Report abuse |
  12. Nikki

    what a load of crap. My 1st born son has autism and my second daughter who is 18 months younger than her brother (who was concieved when 1st born was 9 months) is typically developing.. Research is interesting, but you can say anything causes autism these days.

    January 10, 2011 at 15:46 | Report abuse | Reply
  13. Jorma J. Takala

    Dr William Vasilakis of Lancaster, Ohio

    I saw him during the disability determination phase of my disability case.

    He asked me why I do not already have a Phd.

    After he complained about migraine headaches, I recommended dye free benadryl and explained everything I have been trying to do here.

    After one week, I returned to see him and asked about the migraine headaches, He said wow, You were right, it worked!!!

    I then said that absolutely 100% of his patients are his patients because of the mental health issues caused by their consuming the artificial additives.

    He said, You are right!

    January 10, 2011 at 15:49 | Report abuse | Reply
    • notmyrealname

      Uh-huh. And I'm Queen Elizabeth. Now bow.

      January 10, 2011 at 17:34 | Report abuse |
  14. Imamom23

    I have two children close together – 18 months apart – who are not autistic. If this study is true, I fear it will inhibit parents from having children close in age...and I wouldn't trade that for the world. They are best friends, eternal play mates and suffer no sibling rivalry. I do know a woman who has two children 12 months apart and the second one is autistic, but she was also 40 years old when she delivered him. It has always seemed to me that age of the parents is a factor and as maternal age has risen over the past decade, so has autism rates. I'm not a scientist, but I bet I can conduct a study to prove my theory. You can find a study to prove anything these days.

    January 10, 2011 at 16:28 | Report abuse | Reply
    • cpw789

      There are good reasons for spacing children by 2 years or more but the article states that concern about autism should not be the deciding factor. (If you know that you have the genes for it you might choose to be cautious though.)

      If children close in age seems ideal, just do everything possible to take care of the health needs of the mother. Give her good food, let her rest, and provide her with ample love.

      January 10, 2011 at 22:21 | Report abuse |
  15. notmyrealname

    What is wrong with some of you that you don't understand that this study did NOT say that all children born close together in a family will result in autism? God almighty, go back to school. You can't read or comprehend anything more challenging than "Dick and Jane."

    January 10, 2011 at 17:39 | Report abuse | Reply
  16. Research queen


    January 10, 2011 at 18:19 | Report abuse | Reply
  17. mother of four

    Reeeallly? How do they explain the pre-world-war I generation that was known for huge families of closely spaced children? If this was true, most of our grand parents (and great grand parents) would be autistic. This is right up there with the whole "refrigerator mother" theory from the 1950s. Get the heat off the medical profession. Blame the parents.

    January 10, 2011 at 18:21 | Report abuse | Reply
    • WoodUshutup?

      Blame the parents? For what? For having autistic kids? Oh, you mean it is REALLY the fault of medicine that there is autism? What a moron.

      January 10, 2011 at 19:57 | Report abuse |
  18. ERICA

    The reason there are more autistic children is because they changed the definition of autism. according to alot of these doctors all of us are either autisitic or have adhd. everyone needs to have a condition.

    January 10, 2011 at 19:24 | Report abuse | Reply
    • WoodUshutup?

      No, not true. The "definition" of autism hasn't changed; the diagnostic tools have. "Everyone has to have a condition." Yeah, and yours is the condition of ignorance. Fortunately, it's usually curable. Get help.

      January 10, 2011 at 19:56 | Report abuse |
  19. shan

    There is more proof mercury causes autism than this. Please stop shying away from evidence that the 2001 IOM reports says it cant accept or reject. Thank you.

    January 10, 2011 at 19:44 | Report abuse | Reply
    • WoodUshutup?

      No, there isn't ANY PROOF that mercury causes autism, you simple-minded dolt.

      January 10, 2011 at 19:54 | Report abuse |
  20. WoodUshutup?

    It's simply appalling how many idiotic posts here read something like this: "I have 4 children, all born within a year of each other, and none of THEM is autistic! This article is bogus."

    Good lord. How do you people manage to drive cars when you exhibit that kind of stupidity? Do you not understand the difference between anecdote and statistics? My great-uncle lived to be 100 and smoked a pack of cigarettes every day. Does that prove that if someone ELSE smokes a pack a day he'll live to be 100? What a bunch of morons.

    January 10, 2011 at 19:53 | Report abuse | Reply
    • R. L. Cima, Ph.D.

      Oh good.  An autism expert. My favorite. Bet you've read all the articles and heard all the lectures.  I can tell because you said: "The 'definition' of autism hasn’t changed; the diagnostic tools have."

      What the hell "diagnostic tools" are you talking about? If you mean that the diagnosers – medics, therapists, teachers, you – and everyone else who thinks they're informed – feed off each other and find autism at every turn, these aren't tools – it's bogus "expertise." 

      Been watching this for nearly 30 years and autism has been "linked" to damn near everything.  Lately – the past 10 years – the psychiatrists have been trying to get in on this shameful exploitation of children and families.

      And I also suggest you tone down your contemptuous remarks. Given the crap spread about this, with misinformation and "studies" that make headlines and are NEVER subjected to scientific experiment, it's no wonder the general public is cynical.  

      To repeat from an earlier post of mine – I suggest you read it – autism is neither a disease nor disorder, and the phenomenon is rare, despite the headlines. These are normal kids with special talents in need of special teachers. 

      January 10, 2011 at 22:15 | Report abuse |
  21. G-man

    Wow, it's a wonder all Irish people aren't autistic

    January 10, 2011 at 20:29 | Report abuse | Reply
  22. cpw789

    When children are closely spaced the second child shows signs of stress in many ways. This is why couples have are urged to space babies by 2 or more years. Closely spaced births is associated with more risk for the mother and the infant.

    What this study shows is interesting because closely spaced children causes stress on the second baby by many mechanisms. In this study they seem to have shown the interplay of genetics and environment that seems to be a significant part of development of autism. They did a good in their comparisons. This is not clear from the CNN article, but this research is far from worthless.

    Also recognize that they excluded PDD-NOS, Asperger's and spectrum disorders that are less distinct than straight autism. In other studies similar trends may be found for these, but this has not been done yet.

    January 10, 2011 at 22:15 | Report abuse | Reply
  23. Sharon

    Not make sense because Jenny McCarthy's son is her first child. How can you explained that?

    January 10, 2011 at 23:34 | Report abuse | Reply
  24. Janet

    My two autistic children are five years apart. What's the medical excuse for that? By the by, my son(age 15)is a 3.57GPA student and is not in any RSP/SDC classes. He mainstreamed with other 10th graders. Really, why does he have autism?

    January 11, 2011 at 00:13 | Report abuse | Reply
  25. Dr.GoBlue

    The media does a terrible job explaining the specifics of scientific studies. They seem to be aiming for the emotional responses of readers who have little experience with science, as is clearly demonstrated by many of these comments. It is an irresponsible and immoral practice. Right now, all we can say is that we don't really know what causes autism, but we do know that the incidence of this very complicated and widely variable condition seems to be increasing, even in indigenous populations. We can also say that the ONE study from the 90's linking autism to MMR vaccines used falsified data. All but it's principal investigator have retracted their contributions. The principal investigator was the subject of an investigation and has since lost his medical license. Unfortunately, we will be seeing its impact in the form of measles outbreaks for years to come. Shame on The Lancet, who initially published this study without proper peer review, and shame on the media and self-serving activists who have used it to promote their own agendas to the detriment of our children.

    January 11, 2011 at 00:57 | Report abuse | Reply
  26. Margo

    Kate, autism is not medical diagnosis. It's currently diagnosed by behavior symptoms.

    January 11, 2011 at 02:17 | Report abuse | Reply
  27. Jorma J. Takala

    Again I say and still nobody listens, The cause of autism is EDTA which is made from formaldehyde (Embalming fluid) and sodium cyanide(deadly poison) and petroleum based coal tar FD&C dyes, Artificial flavors and the preservatives BHA, BHT and TBHQ.

    When your funny little studies are done, Youre gonna sit back and say wow that guy was right.

    And until such time, More and More children will be born with autism and other problems, You want studies? Why? Do you really think spending more money on this will help?

    Have all the donations to cancer research saved anyone life?

    Cancer is never cured, It's slowed, But never stopped!

    Autism can be stopped, But that will only happen if parents start paying attention to what they give to their children.
    And especially pregnant women, Pregnant women should not consume ANY Margarine, Mayonnaise, of certain canned foods that are preserved with the EDTA.

    It really is made from formaldehyde and cyanide, Is that really something you want to put into your body?
    A better question might be, Is that something you want to give to your unborn child?

    THINK PEOPLE THINK, Do you need someone to hold your hand while you decide if formaldehyde and cyanide are good, or bad for you?

    I thought America was full of intelligent people, Saying that you need a study to inform you that formaldehyde and cyanide are bad is just as insane as that shooter idiot in Arizona!

    January 11, 2011 at 03:32 | Report abuse | Reply
  28. Jorma J. Takala

    Every parent who has a child with autism, must stop giving them any processed foods, Go totally organic and you will see big changes in your child, I guarantee you will see big changes.

    Is it unreasonable to consider avoiding all fast foods, and delivery pizza, Most pizza joints use margarine type stuff on their breadsticks and in the pans your pizza was made in.

    Try it, What do you have to lose? Your childrens autism?

    If my children had autism I would try anything, Changing their diet and lifestyle to avoid all artifical additives would save money and would not cost you any more than you already spend on food each month.

    Don't just say oh this guy is full of it. Take a chance and see for yourself, see if avoiding the toxic junk helps them be more normal, It worked for me, At the ripe old age of 45 I literally woke up from a chemically induced walking coma. << what I call me AS, or PDD.

    Back to basics!!! Cook at home, make your own stuff at home, It tastes better, costs less and it's good for you!

    January 11, 2011 at 03:39 | Report abuse | Reply
  29. Jorma J. Takala

    lol, oops i forgot to add MSG!

    January 11, 2011 at 03:39 | Report abuse | Reply
  30. Jorma J. Takala

    There are many mitigating factors, IE: Born out on the country side, mom cooked everything at home, The only contact with the additives from that point was later in life when you went out into the world.

    My mother and Father never had any additives in their diet when they grew up in Finland.

    I had problems from the dyes and the EDTA.

    My children were vaccinated and had no problems.

    City folk will have more of these problems than homegrown country folk!

    Many factors, Many different people.

    There is still the environmental side of this as well, Depending on where you lived, the water you drank, Were you close to a factory that spewed out filth into the air?

    All I can say is that when I changed my diet, all of the behavioral and mental health issues that I once had are now gone.

    I had no treatments from anyone, took no meds.

    Changed my diet and lifestyle!

    That's it.

    I am suggesting that some of you try this and see what happens, Nothing thats outrageous, or absurd.

    I know what will happen, But my word is garbage because I am just another moron spouting off and I have nothing to back up my claims other than my whole lifes experiences so I have to leave it up to you to see it for yourselves.

    You can thank me later!

    January 11, 2011 at 03:51 | Report abuse | Reply
  31. Nancy

    Autism was founded many,many years ago before anyhing scientific was studied. Most of the elite founders and makers of the world's living today had autism and was assoicated in making and inventing electricity, airplanes, automobiles, many of our presidents and many others to name, all had autism. Their IQ's were off the chart but they focused their energies on the need to explore and make our world better. If not for them, I would not be on this web page writing this story. These individuals are very smart and intelligent but maybe not as sociable as our society wants. Read the great names associated with Autism and see that if not for them we would still be living in cave like conditions today. To name a few are Wright Bros, Einstein, Henry Ford, Liberace, Benjamin Franklin, and so many others. We have no idea who will be the next great inventor and scientist because we do not understand autism and the intelligence of the mind.

    January 11, 2011 at 04:47 | Report abuse | Reply
  32. Marsha

    Nothing is mentioned about the age of the women whose pregnancies were more closely spaced. Is it possible that women who become mothers at an older age to begin with, decide with their partners to space their children closer together?

    January 11, 2011 at 07:01 | Report abuse | Reply
    • Doug

      This is a good point, but one that they addressed in the research paper. They controlled for partental age (as well as numerous other factors such as income) when analyzing the data.

      Because CNN only provides a brief summary of scientific studies, it is common for CNN to leave out key details such as this one, leading to the many angry, but misinformed, comments that litter this discussion board. If you are interested in the details, it is pretty easy to track down the original paper.

      January 11, 2011 at 10:05 | Report abuse |
  33. Shirin dhalech

    Yaa I've been having 8 kids year after year and I have no problems 🙂

    January 11, 2011 at 07:54 | Report abuse | Reply
  34. Mary

    This study seems flawed to me. If I were in medicine, I'd look to birth control pills and abortions as a more probable cause for autism. Back in my day, many, many families had babies spaced a year apart and I knew of no autistic children. But these are "sacred cows" and would never be linked to something so devastating. For those families dealing with such a traumatic issue, I offer my sincere regrets.

    January 11, 2011 at 13:05 | Report abuse | Reply
  35. Nancy

    In reference to the statement made by R. L. Cima, Ph.D, I agree there is so much talent wasted in clinical studies, for what? . These are wonderful, brilliant and gifted children whom need special teachers to unleash their channel of thoughts and talents to discovery. Who knows what the next big invention would be. These children have higer IQ's than most scientist performing the studies, As I stated before, all our inventions like automobiles, electricity, airplanes, etc were founded by people autistic. Look at your child not as a special child, but as a gifted child, then open his or world to discovery amid other options for developement.

    January 11, 2011 at 23:39 | Report abuse | Reply
  36. Nancy

    I see now that income is a factor in the analysis, OMG, what next? I think these gifted children are born in all walks of life, rich or poor and because they are misunderstood have been labled with a name (autistc)

    January 11, 2011 at 23:48 | Report abuse | Reply
  37. RyanMorris

    Great blog, keeping me from working on articles.
    Good to see more people writing about autism.

    January 21, 2011 at 00:52 | Report abuse | Reply
  38. best discounts upto 90%

    A big shop gifts and up to 90% off on services get cash LAKHS back evey week

    December 25, 2011 at 12:02 | Report abuse | Reply
  39. best discounts upto 90%

    earn enjoy shopping save upto 90% on all products

    December 25, 2011 at 12:03 | Report abuse | Reply
  40. trying to conceive

    Drugs can seriously impact your male fertility. It can also harm your unborn baby. Remember, the first thing to do while figuring out how you are trying to conceive fast is to stop consuming alcohol before getting pregnant

    December 25, 2011 at 14:15 | Report abuse | Reply
  41. world health

    Many people have come to realize that health is the most significant facet that we have to be sure about in our lives.

    January 4, 2012 at 06:53 | Report abuse | Reply
  42. Keneth Priddy

    I've learned some new things via your site. One other thing I'd like to say is always that newer laptop os's have a tendency to allow much more memory to get used, but they furthermore demand more memory simply to operate. If your computer can not handle much more memory plus the newest program requires that memory increase, it can be the time to shop for a new PC. Thanks


    January 7, 2021 at 13:03 | Report abuse | Reply
  43. ClarkTauts

    d3ikq uxxv4 z628

    March 1, 2021 at 16:56 | Report abuse | Reply
1 2

Leave a Reply to Mary


CNN welcomes a lively and courteous discussion as long as you follow the Rules of Conduct set forth in our Terms of Service. Comments are not pre-screened before they post. You agree that anything you post may be used, along with your name and profile picture, in accordance with our Privacy Policy and the license you have granted pursuant to our Terms of Service.

About this blog

Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.