Maternal Infection Requiring Hospitalization During Pregnancy and Autism Spectrum Disorders

4 May

One known possible environmental cause of autism is rubella infections in the mother during a pregnancy. This can lead to a condition called “Congenital Rubella Syndrome”. Many with CRS have very significant disabilities, including intellectual disablity and autism.

The epidemiological team at Aarhus, Denmark, has taken this one step further and looked at maternal infections in general. What they found was that viral infections in the first trimester and bacterial infections in the second trimester are associated with a roughly 3 times greater risk of autism for the child. The infections noted were severe enough to warrant hospitalization.

Maternal Infection Requiring Hospitalization During Pregnancy and Autism Spectrum Disorders.
Atladóttir HO, Thorsen P, Ostergaard L, Schendel DE, Lemcke S, Abdallah M, Parner ET.

Exposure to prenatal infection has been suggested to cause deficiencies in fetal neurodevelopment. In this study we included all children born in Denmark from 1980, through 2005. Diagnoses of autism spectrum disorders (ASDs) and maternal infection were obtained through nationwide registers. Data was analyzed using Cox proportional hazards regression. No association was found between any maternal infection and diagnosis of ASDs in the child when looking at the total period of pregnancy: adjusted hazard ratio = 1.14 (CI: 0.96-1.34). However, admission to hospital due to maternal viral infection in the first trimester and maternal bacterial infection in the second trimester were found to be associated with diagnosis of ASDs in the offspring, adjusted hazard ratio = 2.98 (CI: 1.29-7.15) and adjusted hazard ratio = 1.42 (CI: 1.08-1.87), respectively. Our results support prior hypotheses concerning early prenatal viral infection increasing the risk of ASDs.

8 Responses to “Maternal Infection Requiring Hospitalization During Pregnancy and Autism Spectrum Disorders”

  1. passionlessDrone May 4, 2010 at 23:39 #

    Hi Sullivan –

    Although hospitilizations are nice discrete markers, I’d be surprised if less severe sicknesses didn’t impart some amount of risk as well. My wife was sick damn near her entire fifth month of pregnancy.

    Patterson has a couple of papers regarding IL-6 in animal models that cause behavioral and physiological detriments when given during specific gestational timeframes.

    – pD

    • Sullivan May 4, 2010 at 23:50 #


      I wouldn’t be surprised if you are correct. This would be a much more difficult problem for the epidemiologists to handle, though.

  2. brian May 5, 2010 at 02:26 #

    Yep. Recall that an important mouse model for ASD involves maternal infection with influenza virus, but that infection, per se, is not the major factor, since triggering an innate immune response will do. However, while maternal infections have long been suspected in the development of schizophrenia, to my knowledge no seasonality (suggested of maternal infection during winter months) has been detected for ASD.

    Also OTOH, this study, which might support the need for vaccination for preventable illnesses, may be dismissed because one of the evil co-authors (all of whom presumably study this subject because they hate children) is now living in a Big Pharma-supplied villa on the Riviera after absconding with a billion dollars 🙂

  3. daedalus2u May 5, 2010 at 14:05 #

    There has been a little work on seasonality of autism. The peak seems to be around may-june. This is complicated because it is most likely exposure to something at a certain gestational age that matters, and being premature throws off the birth date vs date of conception correlation.

    Severe weather does increase ASD incidence, and that is seasonal but with different phases in different regions (ice storms vs hurricanes).

    • Sullivan May 5, 2010 at 15:26 #


      in his talk at NIH, Peter Bearman noted that there is no seasonality in the CDDS data he was using.

  4. daedalus2u May 5, 2010 at 17:15 #

    I didn’t see or read his talk. If you look at PubMed there are a few papers that see seasonality. It isn’t a strong effect. It probably isn’t the season per se that affects it, but things that vary with the seasons, like infections, severe weather, diet, day-night length, allergies, SAD, and so on. Some of them likely affect it up and some likely affect it down, so the net signal is complex when the seasonality of those things vary with geographical location.

    Even something like an infection could both increase and decrease the incidence. The immune response results in release of pro and anti-inflammatory cytokines. The precise balance of those cytokines determines whether a particular cellular compartment exhibits pro or anti-inflammatory effects. I think that pro-inflammatory effects in utero would exacerbate ASD symptoms and anti-inflammatory effects would exacerbate schizophrenic-type symptoms. This is consistent with my low NO hypothesis of ASDs.

    Il-6 is a pro-inflammatory cytokine, NO is an anti-inflammatory cytokine. NO is really hard to measure as a cytokine, so usually it isn’t considered. It is the balance between the different cytokines that determines the net effect, and that is really hard to measure, especially because it depends on details of receptor expression that are unknown (and probably unknowable in a particular tissue compartment of a particular patient).

  5. Roger Kulp May 8, 2010 at 19:39 #

    Sullivan,you are a lot more correct than you might think.Not only do many people not go to the hopsital for serious infections, either beause they canot afford it,or because their doctor may not think the infection is severe enough to merit hospitalization,but many infections the mother might have,can remain latent,and dormant years later,and still damage the baby. Tuberculosis is one.

    As some of you may know,my sister and I are both autistic,and have many unexplained medical problems as well.Like many on the spectrum who are also sick,I spent nearly thirty years fighting a hospital who did not believe I had medical problems,and only wanted to throw antidepressants and antipsychotics at me,because they could not see beyond the autism.

    Recently,afer a disatsterous experience with a DAN! doctor,I tried a comletely differet hospital system.One of the first things my new doctor asked me about was if I had ever had a tuberculin test.I hadn’t.I had one,and it was positive,and I will have more tests soon.

    My mother always said I regressed for the first time,after I came home from a hospitalization with meningitis when I was 4-5 months old.She also said I was in an iron lung,so there were pulmonary complications,and lung infections,and GI disease have always been big prolems for all three of us.,as has arthitis with fever for my sister and I.The hospital has long gotten rid of my records from when I was a baby,but it’s very likely it was tuberculosis meningitis.I have also learned my mother had a history of TB herself when she was a baby and child,but like a lot of autism mothers,she didn’t think her history was of imprtance tome.

    While carrying my sister,my mother developed gestational diabetes.I uust pulled up the Danish study from 2004,which seemed to get no attention at the time and yes they DO mention gestational diabetes as increasing the risk for autism.They also mention schizoid personality disorder,which was my original diabgnosis before autism.

    So many of these infections acquired in the womb can lead to medical problems like GI disease in childood,but most mothers would never equate the two.It does take a lot of research,and detective work to find these studies,and to apply them to one’s own families,but far too many autism families do not.Most doctors have not read such studies,and therefore can’t tell their patients about them,even IF they wanted to,because of the doctors who read them,even fewer apply them to their own patients.So the kids are sick,and the parents are told “It’s just a part of autism,we don’t know why.”

    This lack of awareness of the knowledge that is out there,is what leads parets to embrace all sorts of wild antivaccine theories, and go running to questionable or dangerous practitioners.


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