Autism is a puzzle with many pieces. Risk factors like genetics, birth complications, and environmental influences can increase the likelihood of a diagnosis, but they don’t tell the whole story.
One mother I worked with had two sons—one with autism and one without. She often asked, “How can that be, if genetics play such a big role?” It was a powerful reminder that risk factors are not guarantees.
What matters most is recognizing early signs and getting the right support, like in-home ABA therapy.
What Are Autism Risk Factors?
Autism risk factors are characteristics or conditions that may increase the chances of developing autism. They don’t cause autism directly, but they can make it more likely. These factors usually fall into three categories:
- Genetic influences
- Pregnancy and birth-related factors
- Environmental influences
Let’s look at each in more detail.
Genetic Risk Factors
Genetics play one of the biggest roles in autism. Researchers estimate that
up to 80% of autism risk may be linked to genetics.
Family History
- Children with a sibling who has autism are more likely to receive a diagnosis themselves.
- Parents with autism or other developmental conditions may also increase the risk.
Genetic Conditions
Certain syndromes and conditions are strongly associated with autism, including:
- Fragile X syndrome
- Rett syndrome
- Tuberous sclerosis
- Down syndrome (higher prevalence than in the general population)
Gender Differences
- Boys are about
four times more likely to be diagnosed with autism compared to girls.
- Girls may present symptoms differently, which sometimes delays diagnosis.
Pregnancy and Birth-Related Risk Factors
Events that occur before, during, or shortly after birth can also affect autism risk.
Parental Age
- Children born to
older parents, especially fathers, may have a slightly higher risk.
Pregnancy Complications
- Low birth weight
- Premature birth
- Maternal infections during pregnancy
- Diabetes, obesity, or untreated thyroid issues in mothers
Birth Complications
- Lack of oxygen during delivery
- Emergency C-section or traumatic delivery events
Environmental Risk Factors
While genetics set the foundation, environmental factors may also play a role. Research in this area is ongoing, but here’s what’s currently known:
Prenatal Exposure
- Certain medications, such as
valproic acid (used to treat epilepsy), have been linked to higher autism risk.
- Limited evidence suggests maternal exposure to chemicals or pesticides could play a role.
