ADHD and Post-Term Births… Don’t Believe Everything You Read

sleepA new study just came out in the International Journal of Epidemiology, called: “Post-term birth and the risk of behavioural and emotional problems in early childhood”. It was published online on May 3, 2012.

The press have widely reported that this study shows that when a pregnancy goes beyond 42 weeks, then a child is more than two times more likely to develop ADHD in early childhood.

You can find many media references to the study, and here is the link to a BBC article entitled: Overdue babies: ‘Risks for those born after 42 weeks’.

I am largely annoyed with the difference between what the study reports, and what the press are saying.

What The Study Reports:

First of all, this study is very interesting from the perspective that we often think about prematurity as a risk factor for ADHD, as well as other medical, learning and emotional issues. However, we don’t really think of a baby being ‘post dates’ as an issue for ADHD or other emotional or learning issues. The researchers point out that as a pregnancy goes beyond 40 weeks, the placenta may not be able to meet all of the needs of the baby, and thus going past dates may cause problems too.

This study followed the pregnancies of 5145 children in a large population-based prospective cohort study in Rotterdam, The Netherlands. Mothers enrolled between 2001 and 2005. Of the births, 382 (7%) were born post term. The researchers had all of the mothers complete the Child Behavior Checklist (CBCL) at the ages of 1.5 and 3 years old. This questionnaire has parents rate a wide range of symptoms in their children, and then the software calculates the scores, and provides a rating (based on parent report) on several different scales of emotional functioning – such as: anxiety, depression, somatic symptoms, ADHD, aggressive behavior, etc.

Please realize that questionnaires do not diagnose ADHD. Questionnaires can provide data, which can help an experienced clinician to conduct a more detailed assessment to see if ADHD (or any other condition) is actually there.

The research report says: “post-term born children had a higher risk for overall problem behaviour [odds ratio (OR)?=?2.10, 95% confidence interval (CI)?=?1.32–3.36] and were almost two and a half times as likely to have attention deficit / hyperactivity problem behaviour (OR?=?2.44, 95% CI?=?1.38–4.32).”

Let me highlight an important point there: “two and a half times as likely to have attention deficit / hyperactivity problem behaviour“. The questionnaire doesn’t diagnose ADHD, rather it points out that these children have more ‘ADHD problem behavior’ compared to babies born at term.

As an experience clinician and expert in ADHD, I know that it can be very difficult to diagnose kids with ADHD at a young age. It certainly can be done at 3 years old, but I am very cautious about a diagnosis at that age, and I certainly put a lot more work into it than just having the parents fill out a questionnaire. Personally, I would find this information more reliable if the researchers were able to provide follow up at school age – i.e. at 6 years old. That would give us a better idea of how the child was doing (of course I do understand that there are big issues with funding, timing, etc., but I still would love to see data at 6 years old).

Furthermore, I am left wondering: “is the relationship between post-term birth and ‘ADHD problem behavior’ truly a causal relationship?”
In other words, if we accept that the behavior ratings at 3 years old are accurate (i.e. there are more ADHD problem behaviors), then do we know for sure that this was caused by post-term birth?

Maybe there was another variable at play here.

In a cohort of over 5000 women, approximately 4% of them would be expected to have ADHD. That works out to about 200 women. It would be much more likely for these women to have children with ADHD problem behaviors irrespective of when their child was born (premature, on time, or post-dates). And what if they were more likely to refuse intervention from the doctor, and wait for nature to take its course? Then we may believe that it is going ‘post dates’ that is causing ADHD type symptoms, when in fact, we are just screening out for moms who have ADHD symptoms. Now, I have no science to back this up, and I do not believe that the mothers were screened themselves for ADHD. So this is complete conjecture. But, I think it’s an interesting theory.

Before I get flaming comments here, I’m not suggesting that women who refuse induction of labor, or who want to let nature take its course all have ADHD. Far from it. I’m just putting forward a theory which may refute the theory that it is a causal relationship between post-dates birth and developing ADHD.

What The Media Is Reporting:

The media is reporting that kids born post-dates (i.e. after 42 weeks) are over 2 times as likely to have ADHD. I read one report which went so far as to suggest that mothers should consider having a C-section before 42 weeks to help to prevent ADHD (I can’t find the exact news report to link to here, but trust me, I read it).

In Summary:
As you can see based on what I wrote above, I believe that these claims are over-simplified. I am not convinced that post-term births increase the risk of ADHD. This study has opened my eyes to the possibility that post-term births may be a risk factor for ADHD, or possibly other learning or behavioral issues, but it is by no means conclusive research. It’s my opinion that the media are over-simplifying this, and it may create more backlash and stigma for ADHD patients and their moms (like the mother-in-law saying: “I told you you should have listened to the doctor and had an induction of your labor at 41 weeks. The fact that you waited too long caused my grandson’s ADHD…”).

What do you think? How do you respond to the research, and the media reporting of it?
Please share your thoughts and comments below.

Dr. Kenny


  1. I was born 3 weeks premature in the 60’s and am as ADHD as you can get. My nephew (11 years) and niece (7 years old) both have ADHD and were both very premature. My 9 year old niece who was full term does not have ADHD.

  2. Add to this the uncertainty about determining when a baby is 38 or 40 or 42 weeks old. A young friend was pressured to have a Caesarian section because her baby was past due only to hear after it was done, “Oh, the ultrasound was incorrect, your baby was younger than we thought.”

    Inaccurate “sound bite” reporting of this type of research is not helpful to anyone in any way.

  3. Hello:

    As both a mother of an ADHD child born 12 days past due date, and a clinician serving ADHD’ers, I completely agree with you. My first thought on reading the survey data was the genetic links were being ignored in the reporting.

    I recall in the haze of decision-making being told that I needed to be induced to avoid the placenta breaking down, but nothing about ADHD.

    I am much more certain the traits of ADHD came from mom and dad.

    Let’s not pile on any more guilt to mothers who couldn’t get that baby to come out on time – for example, me delivering at 42. My OBG made the best decision possible going to induction.

    Mary Lynn Trotter MSW RSW

  4. The link reported in that study wouldn’t explain ADHD in our family at all. I have four children and a husband with ADHD. The child with the least severe symptoms was the one born at 42 weeks. The other three children were born just inside of 40 weeks and all have much more severe symptoms as accompanying sensory disorders. My husband was born close to week 40 as well. I agree that genetics are a much greater factor.

  5. Completely agree with criticism in the publishing of supposed implications of this study. There is no cause and effect established with any degree of scientific rigour-this is a questionable link at best. This is not a long term study either. I fail to recognize, in this study, many variables from the genetic environment, educational environment, and social environment that would normally be included in research results worthy of alerting mothers to be, or the medical community to recommend any changes in their birthing plans.

  6. Both of my children were over 10 days past due and both have attention issues, but my oldest is 20 years old, graduated HS at 16 and went straight on to college, my 7 year old son has been diagnosed, and is a straight A student. I disagree with the article, due to the fact that I believe environment, foods, and genetics may play a much larger role.

  7. I have run pre-school and nurseries in the Uk for 17 years and am the Mum of an ADHD child who was just 5 days overdue.
    My child exhibited a lot of signs in his early years (under 4) that I can now put down to ADHD (eating habits, unceasing biting and behaioural signs of frustration, inability to complete tasks or listen). Although I knew that all was not right for him at an early age, I would not have been so bold as to think of ADHD at the time – even though it runs in the family and I have seen signs in my nephew too at an early age.
    My son was 6 when he was diagnosed with ADHD. I have never been able to recognise ADHD in children attendng my nursery (4 and under). I can recognise some signs in some children but would not want to pigeon hole them at that age. I would expect a lot of children to grow out of their issues by the time they reach grade 1. The rate of maturity in boys being very varied.
    The children who have pronounced differences that are recognozable at an early age, would more likey be diagnosed with aspergers/autism at this early stage.
    I would agree that a reassessment at 6 yrs old would be much more valid than a single diagnosis at 3. Also, the study gathers it’s information from parents alone. Many of these parents may have no other experience with children so their view of their child may be resulting in an over-emphasis of behavioural issues.
    This study was also carried out in Holland. There are many lifestyle habits of the parents that I would like to see evaluated in the study.
    I saw the article in the UKs daily mail newspaper and also saw your comments. I do agree with you. I personally feel that there are far better reasons for inducing birth anyway at 42 weeks. I was reluctant to go over 41 weeks because I would prefer a live birth after being pregnant for 9 months!!

  8. A major indicator that a child may have ADHD is that a parent has it. That being the case, then post-date births might run in the family as well. Of course, there is no data, which suggests to me we shouldn’t jump to conclusions.

  9. Am the mother, daughter, sister and granddaughter of people with ADHD (I do not have ADHD myself). I also ran a support group for parents of children with ADHD for many years, and many of these parents had ADHD themselves (whether or not THEY were aware of it). Personal experience has shown me that genetics plays an incredible role in whether or not someone will be born with ADHD. Perhaps not the only way, but if there is ADHD in your family, offspring are most certainly “at risk” of inheriting this. I obviously carry this gene as one of my children has ADHD even though I do not. Not everyone gets that “trait”, just as there are siblings with different color hair, eyes, etc. I truly do not understand why the medical community is so reticent to discuss the genetics of this affliction. And yes, I am calling it an affliction — life is just tougher for these folks. I know — I have lived with it all my life in one role or another (see first sentence).

  10. My eldest was 42 weeks gest. He has Aspergers and anxiety. My youngest born scheduled csection at 38-6 is severly impulsive ADHD…and is 5 now.

  11. Having a child with ADHD, a terrible pregnancy that had me suffering preterm labour at 22 weeks, complete bed rest for 6 months and then a late delivery (42.5 weeks) because nobody wanted to touch my case as my doctor had gone on holidays. I laboured for 2 days and finally was given a c-section, I have wondered alot about all the factors that may have contributed to my son`s ADHD. I do think that having a late delivery, since he was 10.6 lbs at birth negatively affected my son developmentally and there may be some validity to this. I am not sure how much but if other people have experienced the same, then it is possible there is some correlation. Ideally a baby is born on time and about 7 lbs, so I wonder how many average sized babies on a regular delivery schedule have ADHD. Kenny can you answer this?

  12. i have 6 children but my youngest son is the only one that have adhd he was born 2 weeks early but i was 43 when i had i was told that adhd comes from the mothers side of the family but i love him more even with all his problems

  13. I have 4 kids. #1 was born at 41 weeks, #2 was born at 40 weeks, #3 was born at 38 weeks (emergency cesarean), and #4 was born at 39 weeks. The first 3 I went in to labor, #4 was a scheduled cesarean rather than doing a VBAC. Guess which one is my ADHD child – #3, the one born earliest. The one born at 41 weeks is actually the one I can best say is neurotypical. While I know that my personal experience is not necessarily valid research, I do agree that these claims are oversimplified, much in the same way as the article I recently saw that links autism to moms being overweight during pregnancy.

  14. First of all, I want to point out to the press that having a c-section is not the only way to prevent going past 41 weeks. You can be induced.
    I have ADD, not diagnosed until 55 years old. Mom said I was a week late. My brother may be ADHD, I don’t know, if he has it or if he was born late. My daughters were born 2, 2 1/2 and 3 weeks late. One had behavioral problems starting in preschool age and it got worse through the years. she was placed in a children’s home at 16 1/2. The other 2 daughters had emotional problems starting at preschool age. These got worse in the teenage years. My 2 oldest kids were abused by an aunt who was babysitting them while I was in the hospital having the 3rd one. This likely led to some of the emotional problems. My doctors refused to induce labor, telling me there is no such thing as an overdue baby. My third daughter was just like a month old baby the day she was born, she followed my finger with her eyes, up, down, across and in a circle, she had no vernix on her. Her other behaviors were just like a one month old. My son, the 4th kid, was the only one born on time and he was diagnosed ADHD at 9 years old. He continues at 26 years old to have concentration problems and other problems related to adult ADD. He weighed 10 pounds, had a very large head. I wonder if his size had something to do with his having ADHD.

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  16. Kenny,
    Thank you for this clarification. Both my girls were born near and at 42 weeks and I suspect LD runs in my husband’s family (no one talks about it). My girls seem to be healthy typically developing kids but, given both these factors, I was riveted to this story for awhile. There is so much going on today when it comes to kids and development challenges; it’s easy for a parent to get swept up in a media frenzy. We are lucky to have a voice of reason in you!

    Best to you,

  17. I was born at 23 weeks gestation, and I weighed 1 pound 6.8 ounces. The doctors said that I would not survive past a couple of weeks, and if I did, that I would be deaf, blind, stupid, and all sorts of other things. There was a baby in that same hospital that was born later than me but still premature, and weighed heavier, and that baby died a few days after it was born. My cousin on my mothers side has ADHD and he was unmedicated and struggling with cigarettes and other drugs until 5 or 6 years ago, something like that. My grandfather died from emphysema caused by smoking. I have the inattentive subtype of ADHD and my father has ADHD, but I have no idea what he is, probably inattentive also. He has been treating himself with an anti-artificial diet. My mom and dad have been divorced since around 10 years ago. My dad has two ex-wives now, my mom and a really nice lady named Troi. The divorce of my mom and him was mutual, but my dad said that divorced Troi because her oldest daughter was too much to handle. Now I have an great ex-step-mom, an awesome step-dad, a cute half brother, and a ridiculously huge family. My dad was in a relationship with this one lady that had around 4 or 6 kids, most of them were twin, but they broke up a few months ago. My mom, my dad, and my step-dad are all great friends, which is awesome. I have no idea why I am posting this, so sorry if this is just a weird ramble. Thank you so much for this blog.

  18. This is so old but I’m going to leave a comment here anyway. I have three boys, two very much ADHD inattentive and one neurotypical. Both of my ADHD babies were born at 39 wks via c-section, and my neurotypical was my last born at 42w2d. Given that I probably gestate a little longer than the average bear I would bet my older two were a little early. Also, my husband has ADHD, it’s not diagnosed but when you live with someone long enough you realize that those little apples didn’t fall far from any tree. They are far more severe than he is though. Who knows.

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