flu infection during pregnancy is not related to increased incidence of autism
in the child according to a recent study conducted by Ousseny Zerbo, Ph.D., of
Kaiser Permanente Northern California, Oakland, and co-authors.
‘Maternal flu during pregnancy is not associated with increased risk of autism spectrum disorders.’
Aim of the Study
The study authors wanted to assess whether maternal flu during pregnancy
and administration of the flu vaccine was associated with an increased risk of autism spectrum disorders in the baby.
Details and Findings of the Study
involved over 196,000 children born between 2000 and 2010 at a minimum
gestational age of 24 weeks.
included 1,400 mothers (0.7 percent) who were diagnosed with influenza and
45,231 mothers (23 percent) who were administered flu vaccination during pregnancy
children (1.6 percent) were diagnosed with ASD.
authors submit that influenza infection during pregnancy or vaccination during
the second and third trimesters of pregnancy does not lead to a higher
incidence of autism
or autism spectrum
disorders. There might have been a hint of an increased risk of ASD with
maternal influenza vaccination during the first trimester. However, the authors
believe the finding was not statistically significant after adjusting for
multiple comparisons, and was probably due to chance.
found no association between ASD risk and influenza infection during pregnancy
or influenza vaccination during the second to third trimester of pregnancy.
However, there was a suggestion of increased ASD risk among children whose
mothers received influenza vaccinations early in pregnancy, although the
association was insignificant after statistical correction for multiple
Limitations of the Study
study admits to several limitations, including determination of ASD status by
diagnoses on medical records which were not formally validated by standardized
clinical assessment for all cases. Moreover, it was not possible for the
researchers to control other possible mitigating factors.
we do not advocate changes in vaccine policy or practice, we believe that
additional studies are warranted to further evaluate any potential associations
between first-trimester maternal influenza vaccination and autism," the
Autism Spectrum Disorder
- In Brief
spectrum disorder is a developmental disorder characterized by impaired
reciprocal social interaction and communication, and also stereotyped
prevalence rates of ASD are estimated to be about 1 percent in children as well
as adults. ASD is more common in boys with an overall
4:1, though this may vary across the spectrum of autism disorders.
etiology of ASD is considered to be multifactorial, with a complex interplay
between genetic and environmental influences, many of them yet to be fully
Genetic Factors in ASD
on chromosomes 2q, 7q, 15q, and 16p have been suggested as possible locations
of susceptibility genes of ASD. Cerebellar developmental patterning gene
ENGRAILED 2 has also been linked to ASD susceptibility.
genes as well as serotonin transporter genes have been implicated.
Environmental Factors in ASD
- Prenatal factors such as increased
maternal age, drugs such as thalidomide,
anticonvulsants, diabetes in the mother, and some viral infections such as
influenza, maternal rubella and cytomegalovirus and MMR and influenza vaccines
have also been variously implicated in ASD.
- Birth related
factors such as low birth weight, birth asphyxia (weak
premature birth have also been suggested as possible causes for
- Post natal factors such as viral infections, mercury
toxicity, autoimmune diseases
are also suggested to be possible risk factors for development of
advances made in the field of genetics have led to a better understanding of
the molecular and cellular basis of ASD. However, the contribution of
environmental factors having additive or multiplicative effects need to be
further studied. It is felt that more funding needs to be dedicated to this
area of research, which until now has not received enough backing or funding.
- Autism risk factors: genes, environment, and gene-environment
interactions - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3513682/)
- Is Maternal
Influenza or Fever During Pregnancy Associated with Autism or Developmental
Delays? Results from the CHARGE (CHildhood Autism Risks from Genetics and
Environment) Study - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3484245/)
- The negative impact of Influenza infection during
pregnancy - (http://www.influenza.org.nz/negative-impact-influenza-infection-during-pregnancy)
Do Not Cause Autism - (http://www.cdc.gov/vaccinesafety/concerns/autism.html)
about Seasonal Flu and Flu Vaccines - (http://www.cdc.gov/flu/about/qa/misconceptions.htm)