JIIMC March 2016.cdr


ORIGINAL ARTICLE

ABSTRACT
Objective: To determine the frequency of different prenatal risk factors associated with autism spectrum 
disease.
Study Design: A Case-control study.
Place and Duration of Study: The Study was conducted at Rawalpindi. Cases were recruited from Autism 
resource centre (ARC), Step to learn (STL) Rawalpindi, Hassan academy for special children, and Army public 
academy for special children Rawalpindi and controls from DHQ hospital Rawalpindi from February 2014 to 
January 2015.
Materials and Methods: Two groups of children were included in the study, Group one were diagnosed case of 
autism ASD (n=101) aged between 3 to 10 years and Group two (control n=233). The data was collected and 
entered in a self designed structured questionnaire. Data was analyzed by SPSS (Statistical Package for the 
Social Sciences) Vs 20.
Results: Over 30 risk factors have been identified. 67.3% cases were males and 32.6% were females whereas 
34% controls were males and 66% controls were females. The factors associated with autism were male gender, 
advanced father's age at child birth, severe iron deficiency anemia during pregnancy, vitamin D deficiency, 
maternal hypothyroidism, asthma, hypertension, diabetes mellitus and obesity, high stress during pregnancy, 
C-section, valporoic acid use, antidepressants and antibiotics use in mothers, infection during pregnancy, no or 
minimum exposure of sunlight during pregnancy, premature birth, Meconium aspiration syndrome and late 
cry, blood group incompatibility with mothers and Rh incompatibility between mothers and fathers.
Conclusion: Prenatal risk factors like stress, vitamin D deficiency, iron deficiency anemia, hypothyroidism, 
obesity, diabetes, blood group incompatibility with mothers, children born in spring and C section are the 
strong causes to develop autism in children.

Key Words: Autism, Neurodevelopmental Disorder, Risk Factors.

learning, cognitive functioning, sensory processing 
1

and attention.  The phrase “spectrum disorders” is 
used to point out that ASDs include a variety of 
behaviorally concerned conditions, which are 
diagnosed by clinical observation of development. 
These conditions encompass autistic disorder (i.e., 
autism), and pervasive developmental disorder and 

2
Asperger disorder.  ASDs, related to other 
neurodevelopment disabilities, are usually not 
curable and chronic maintenance, preservation   and 
management is requisite. Regardless of the fact 
outcomes are diverse and specific behavioral 
characteristics vary over time, the majority of 
children with ASDs remains within the spectrum like 
adults and, disregarding of their intellectual level, 
undergo to experience problems with employment, 
independent and self-regulating living, communal 

3,4
relationships, mental health and societal problem.  
The diagnostic criteria depend upon the symptoms 
that become evident before a child is three years 

5
old.  Causative factors for autism are inadequately 

Introduction
Autism is a wide-ranging term used to illustrate an 
assemblage of complex neurodevelopmental 
disorders also known as Pervasive Developmental 
Disorders (PDD) or Autism Spectrum Disorders 
(ASD). ASDs are a collection of developmental 
disabilities characterized by atypical development in 
socialization believe behavior and communication. 
Symptoms of ASDs are present before age 3 years 
and frequently are accompanied by difficulty in 

Frequency of Different Risk Factors of Autism Spectrum Disease:
A Multicentre Comparative Study

1 2 3 4
Saira Jahan , Zahra Arshad , Sana Nasir Zaidi , Imran Amjad

Evaluating Different Risk Factors of ASDJIIMC 2016 Vol. 11, No.1  

Correspondence:
Dr. Saira Jahan
Department of Rehabilitation Sciences
Riphah International University 
Railway General Hospital, Rawalpindi
E-mail: jdrsyri@yahoo.com

1,2,3
Department of Rehabilitation Sciences

Riphah International University
Railway General Hospital, Rawalpindi
4
Riphah College of Rehabilitation Sciences

Riphah International University, Islamabad

Funding Source: NIL ; Conflict of Interest: NIL
Received: November 18, 2015; Accepted: March 10, 2016

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understood. Both environmental and genetic risk 
factors are likely to commit etiology. Although 
autism appears to have its roots in very early brain 
development, mainly identifiable signs and 
symptoms are likely to appear between two and 
three years of age. Mostly parents are the first to 
note and identify that their child is presenting a 
typical behaviors such as deteriorating to make eye 
contact, not answering to his or her name or playing 

6
with toys in unusual, repetitive behavior.  The 
purpose of this study is to determine the frequency 
of different prenatal risk factors associated with ASD 
so that these new risk factors should be used to make 
recommendations for clinical practice and by the 
avoidance of these risk factors, prevalence of ASD 
decreases.

Materials and Methods
It was a multicentre case control study. There were 
total 334 children enlisted in this study in which 101 
were diagnosed case of autism and 233 healthy 
controls were taken with no neurological, 
musculoskeletal or cardiopulmonary abnormalities. 
Non probability convenient sampling technique was 
used. The Case data was collected from ARC (Autism 
Resource Center, Rawalpindi), STL (Step to Learn), 
Hassan academy for special children, Rawalpindi and 
Islamabad branch and Army Public Academy for 
special children Rawalpindi. Control data was 
collected from DHQ Hospital, Fauji Foundation 
H o s p ita l R awa lp in d i, Nat io n a l I n st it u te o f  
Rehabilitation and Medicine Islamabad, Railway 
General Hospital Rawalpindi and Divisional Public 
School Rawalpindi from January 2014 to December 
2014.Permission was taken from respective 
institutes.
Data Collection Tool and Procedure: A self designed 
structured questionnaire was used for data 
collection. The questionnaire had 33 items 
(Appendix A). The different risk factors causing 
autism included in our questionnaire were based on 
literature search different studies in different 
settings by different authors. It included Iron 
deficiency anemia, vitamin D deficiency in mother 
during pregnancy, older parents, C section, mother 
high stress level during pregnancy due to any reason, 
blood group incompatibility with mother and many 
more. Ethical permission was taken from Medical 
Superintendent of DHQ, FFH, NIRM and PRH. After 

obtaining informed consent from parents, data was 
c o l l e c t e d  u s i n g  s e l f  d e s i g n e d  s t r u c t u r e d  
questionnaires. Questions were first explain and 
then asked from parents of study groups. Data was 
filled personally by the authors.
Statistical Analysis: Data was analyzed by using SPSS 
(statistical package for social sciences) VS 20.

Results
30.2% ASD cases and 69.7% healthy controls were 
taken in this study. In ASD cases 6.9% mothers were 
suffering from obesity and 11.8% from diabetes and 
21% from hypothyroidism (Fig 1). Table I show Stress 
mothers taken during pregnancy, infection during 
pregnancy, exposure of sunlight during pregnancy, 
premature births, C section, episiotomy, SVD, 
meconium aspiration syndrome, late cry of baby at 
birth, Different Rh and different blood group among 
parents and blood group incompatibility with 
mothers. Controls had lesser frequency of iron 
deficiency anemia during pregnancy whereas ASD 
cases had prevalence of moderate and severe iron 
deficiency anemia during pregnancy increases in 
mothers of cases (Fig 2). 70.27% mothers of children 
with ASD used folic acid and vitamin D during 
pregnancy whereas less usage in mothers of 
controls. Mothers of children with ASD had history of 
more usage of valproic acid, antidepressant and 
antibiotics i.e. 6.9%, 22.7% and 14.8% respectively 
whereas only 2.57% mothers of controls used 
antidepressant and 3.0% used antibiotics and none 
used valproic acid.

Fig 1: Comparison of Mother's medical history between 
cases and controls

Evaluating Different Risk Factors of ASDJIIMC 2016 Vol. 11, No.1  

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Discussion
In our study 67% cases of autism were found out to 
be males and only 29% were females hence 
supporting male gender as a risk factor of autism. 
Males are at higher risk for neurodevelopmental 
disorders, such as autism spectrum disorder (ASD), 
than females, but the fundamental reasons have 

7
been uncertain.
Scientists have supposed a connection between iron 
deficiency and autism spectrum disorder. In a study 
maternal intake of supplemental iron and risk for 
autism spectrum disorders by Schmidt RJ, et al 

establishes a strong relationship between iron 
8

deficiency and autism.  In our study 48% severe 
deficiency of iron is found in cases and only 5% 
severe deficiency is found in controls. 9% of the cases 
had no iron deficiency while 61% of the controls also 
did not have any iron deficiency. This signifies the 
iron deficiency as one of the contributory risk factors 
for development of ASD. According to Kinney DK et 
al, in their study, “prenatal stress and risk for autism” 
stress of expectant mother is a noticeable reason for 

9
the symptoms of autism.  In another study “timing of 
prenatal stressors and autism” by Beversd of DQ et 
al, it was reported that prenatal stress has a role in 

10
causing autism.  In our study 42% cases had self-
reported moderate to severe stress during their 
pregnancies and only 14.5% of controls also reported 
stress. So we can deduct the conclusion that stress is 
as one of the risk factor for ASD.
A prospective study of Exposure to valproic acid and 
risk for autism spectrum disorder indicates that 
valproic acid usage may be an important factor in 

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causing autism.  In our study 6.9% cases taken 
valproic acid during pregnancy (anti- seizure 
medicine) whereas none of the control took valproic 
acid. This finding is in agreement with previous 
studies but further investigation is warranted. 
Prenatal exposure to SSRIs, particularly during the 
first trimester, may moderately increase the risk of 

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ASDs.  22% cases in our study used antidepressant 
during pregnancy whereas only 2% controls were on 
a n t i d e p r e s s a n t  i n d i c a t i n g  e i t h e r  i t ' s  t h e  
antidepressant drugs or the depression which is 
hidden behind and need further investigation.
Studies showed that antibiotic use in pregnancy 

13
might cause autism.  In our study 14% cases took 
antibiotics during pregnancy whereas only 3% 
controls  took antibiotics during pregnancy but the 
need is  to investigate the group of antibiotic, dose, 
frequency and all the minor details, so further 
investigation is warranted. Drugs possibly will 
activate the disease, earlier researchers found that 
use of medications during pregnancy may have an 
effect on the developing fetus and may cause 

13
autism.  In our study  55% cases taken no drug 
during pregnancy emphasizing that it is not only the 
drugs that causes autism, there are some other 
factors that may in combination with the drugs 
causes autism.

Table I: Comparison of different condi�ons between
cases and controls

Fig 2: Comparison of Iron deficiency anemia between 
cases and controls

Evaluating Different Risk Factors of ASDJIIMC 2016 Vol. 11, No.1  

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Conclusion
Prenatal risk factors like stress, vitamin D deficiency, 
iron deficiency anemia, hypothyroidism, obesity, 
diabetes, blood group incompatibility with mothers, 
children born in spring and C section are the strong 
causes to develop autism in children. It is concluded 
that there is insufficient evidence to implicate any 
one prenatal factor in autism etiology, although 
there is some evidence to suggest that exposure to 
pregnancy complications may increase the risk.

REFERENCES
1. DeStefano F, Bhasin TK, Thompson WW, Yeargin-

Allsopp M, Boyle C. Age at first measles-mumps 
rubella vaccination in children with autism and school 
matched control subjects: a population-based study 
in metropolitan Atlanta. Pediatrics. 2004; 113: 259-
66.

2. Braun KVN, Pettygrove S, Daniels J, Miller L, Nicholas J, 
Baio J, et al. Evaluation of a methodology for a 
collaborative multiple source surveillance network 
for autism spectrum disorders -Autism and 
Developmental Disabilities Monitoring Network, 14 
sites, United States, 2002. MMWR Surveillance 
summaries: Morbidity and mortality weekly report 
Surveillance summaries/CDC. 2007; 56: 29-40.

3. Howlin P, Goode S, Hutton J, Rutter M. Adult outcome 
for children with autism. Journal of Child Psychology 
and Psychiatry. 2004; 45: 212-9.

4. Friedman ND, Warfield ME, Parish SL. Transition to 
adulthood for individuals with autism spectrum 
disorder: current issues and future perspectives. 
Neuropsychiatry. 2013; 3: 181-92.

5. Baharara J, Hojjati M, Rasti H. The Ratio of Second to 
Fourth Digit Length (2D: 4D) in Children with Autistic 
Disorder. International Journal of Pediatrics. 2014; 2: 
5-11.

6. Lord C, Paul R. Language and communication in 
autism. Handbook of autism and pervasive 
developmental disorders. 1997; 2: 195-225.

7. Robinson EB, Koenen KC, McCormick MC, Munir K, 
Hallett V, Happe F, et al. Evidence that autistic traits 
show the same etiology in the general population and 
at the quantitative extremes (5%, 2.5%, and 1%). 
Archives of general psychiatry. 2011; 68: 1113-21.

8. Schmidt RJ, Tancredi DJ, Krakowiak P, Hansen RL, 
Ozonoff S. Maternal Intake of Supplemental Iron and 
Risk of Autism Spectrum Disorder. American Journal 
of Epidemiology. 2014: kwu208.

9. Kinney DK, Munir KM, Crowley DJ, Miller AM. Prenatal 
s t r e s s  a n d  r i s k  fo r  a u t i s m .  N e u ro s c i e n c e  
&Biobehavioral Reviews. 2008; 32: 1519-32.

10. Beversdorf DQ, Manning S, Hillier A, Anderson S, 
Nordgren R, Walters S, et al. Timing of prenatal 
stressors and autism. Journal of autism and 
developmental disorders. 2005; 35: 471-8.

11. Christensen J, Gronborg TK, Sorensen MJ, Schendel D, 
Parner ET, Pedersen LH, et al. Prenatal valproate 
exposure and risk of autism spectrum disorders and 
childhood autism. Jama. 2013; 309: 1696-703.

12. Croen LA, Grether JK, Yoshida CK, Odouli R, Hendrick 
V. Antidepressant use during pregnancy and 
childhood autism spectrum disorders. Archives of 
general psychiatry. 2011; 68: 1104-12.

13. Atladottir HO, Henriksen TB, Schendel DE, Parner ET. 
Autism after infection, febrile episodes, and 
antibiotic use during pregnancy: an exploratory 
study. Pediatrics. 2012; 130: 1447-54.

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