The Hidden Autism Risk Factors Every Parent Should Be Aware Of

Key Highlights

• Autism spectrum disorder (ASD) is a complex condition influenced by both genetic and environmental factors.
• The risk of autism is higher with a family history of the disorder, pointing to strong genetic factors.
• Environmental factors, particularly prenatal exposures to certain medications, illnesses, and pollutants, can affect brain development.
• Advanced parental age for both the mother and father is an established risk factor for having a child with ASD.
• Complications during birth, such as premature delivery or low birth weight, are also associated with an increased risk.
• The prevalence of autism is higher in boys, but different symptom presentation may lead to under-diagnosis in girls.

Autism research has advanced significantly, giving us a clearer picture of the many factors that may influence development. Understanding these factors can help families approach the topic with more clarity and less uncertainty.

I’ve sat across from many parents who ask, “Did I do something wrong?” One mother in particular broke down in tears, convinced her stressful pregnancy was to blame. 

Sharing the science—and reassuring her she hadn’t caused her child’s autism—was a turning point in her confidence as a parent.

Genetic Risk Factors for Autism

Genetics is one of the most thoroughly researched components of autism risk. What we know today reflects a complex interplay of inherited traits and spontaneous genetic changes.



Heritability of Autism Spectrum Disorder

Twin studies consistently show that autism is highly heritable. Identical twins have a much higher likelihood of both being autistic compared to fraternal twins. 

But because identical twins aren’t always both diagnosed, genetics clearly aren’t the entire story—environmental factors matter too.

Common Genetic Syndromes Linked to Autism

Certain genetic syndromes have a higher likelihood of co-occurring with autism. These cases help us understand specific neurological pathways. Common examples include:

• Fragile X syndrome
• Rett syndrome
• Tuberous sclerosis

Specific Gene Mutations and Variants

Rather than a single “autism gene,” ASD results from many genetic variations. These can range from very small changes (SNPs) to larger copy number variants (CNVs). Some CNVs occur spontaneously and can influence brain development in meaningful ways.

Family History and Recurrence Risks

When one child in a family is diagnosed with autism, the chances of a sibling also receiving a diagnosis increase significantly. Family histories of autoimmune disorders may also point to shared biological pathways.



Chromosomal Abnormalities Impacting ASD

Larger chromosomal changes—like deletions or duplications—can disrupt several genes at once. Some CNVs have strong links to ASD, and when combined with environmental stressors, effects can become more pronounced.

Advances in Genetic Testing for Autism

Genetic testing for autism is more accessible than ever. It can identify certain variants and CNVs and provide families with helpful insight about diagnosis, future pregnancies, and community connection. Research continues to refine these tools for more personalized support.

Environmental Risk Factors Related to Pregnancy

Pregnancy is a key developmental window, and environmental exposures during this time can influence neurological development.

Maternal Health During Pregnancy

A mother’s overall health—especially metabolic and immune factors—can shape the prenatal environment. Conditions like diabetes, obesity, or chronic inflammation can influence fetal development.

My goal when supporting families is never to assign blame—just to provide clear information about what research shows.

Prenatal Exposure to Infections and Illnesses

Infections and high fever during pregnancy may increase autism risk, particularly during early trimesters. The immune response—not the infection itself—appears to be the key factor. Managing fever or illness under medical supervision is important for fetal health.

Impact of Nutrition and Folic Acid Intake

Nutrients like folic acid and vitamin D support fetal brain development. Low folic acid intake, especially early in pregnancy, has been associated with higher odds of ASD in some research. Proper supplementation can create a more supportive developmental environment.

Effects of Prenatal Medication Use

Some medications, like valproic acid, are known to increase autism risk when taken during pregnancy.

Others, such as certain antidepressants, show mixed findings because the underlying conditions also play a role. Discussions with a healthcare provider are essential before starting or stopping any medication.

Influence of Maternal Lifestyle Choices

Lifestyle choices such as smoking or cannabis use may contribute to developmental challenges. Avoiding these exposures where possible helps support healthier outcomes.

Stress Levels During Pregnancy

Chronic stress can affect hormonal and immune responses, which may influence fetal development. Supporting mental well-being during pregnancy benefits both the parent and the baby.

Parental Age-Related Factors

Age at conception is another important factor, influencing genetic stability and overall pregnancy outcomes.

How Advanced Maternal Age Affects Autism Risk

Older maternal age has been linked to increased autism likelihood due to age-related genetic changes in eggs. Most children born to older parents are healthy, but understanding this trend is helpful for family planning.

Paternal Age and Genetic Mutations

Because sperm are produced continuously throughout a man’s life, genetic mutations can accumulate over time. Older paternal age is associated with more of these de novo mutations that can influence ASD risk.

Age-Related Fertility Treatments and Their Effects

Some research suggests slightly higher ASD rates in children conceived through fertility treatments, though this may reflect parental age or other health factors rather than the treatments themselves.

Research on Age Gap Between Parents

A large age difference between parents has also been associated with increased autism risk, though the reasons aren’t yet clear.

Complications During Birth and Neonatal Factors

Birth and early neonatal experiences can add stress during a critical stage of brain development.

Premature Birth and Low Birth Weight

Premature infants or those with low birth weight face higher risks of developmental challenges, including ASD. The last weeks of pregnancy are essential for brain growth, and early birth can interrupt that process.

Delivery Methods and Associated Risks

A slight association has been found between cesarean deliveries and higher autism rates, though the underlying medical reasons for the C-section may be the true link.

Birth Trauma or Hypoxia

Events that cause oxygen deprivation during birth can affect early brain development. These complications increase vulnerability but don’t directly cause autism.

Neonatal Jaundice or Infections

Untreated jaundice or early infections can stress a newborn’s neurological system. Prompt treatment greatly reduces risks, but these conditions are still recognized contributors.

Role of NICU Admissions

NICU admission often signals earlier health complications, many of which are linked to higher developmental risks. The NICU stay itself isn't the cause—it's the underlying health issues that matter.

Maternal Medical Conditions Influencing Autism Risk

Long-standing medical conditions can influence pregnancy and fetal development in important ways.

Diabetes and Hypertension During Pregnancy

These conditions can affect blood flow, oxygenation, and nutrient supply to the fetus. Managing them carefully during pregnancy is important for minimizing risks.

Autoimmune Disorders and Challenges

Autoimmune conditions can create chronic inflammation or circulate antibodies that sometimes interact with fetal brain development.

Thyroid Problems in Mothers

Thyroid hormones play a crucial role early in pregnancy. Untreated hypothyroidism increases risks for developmental delays and may contribute to ASD.

Mental Health Issues and Stress

Maternal anxiety or depression can influence fetal development through stress hormones and shared genetic factors. Supporting mental health throughout pregnancy is essential.

Medications for Chronic Conditions

Some medications needed to manage chronic conditions may elevate neurodevelopmental risks, but stopping them can also be dangerous. This is why individualized medical planning is so important.

Early Childhood Health and Environmental Exposures

After birth, children continue to develop rapidly, and certain environmental exposures can influence that trajectory.

Effects of Environmental Pollutants and Toxins

Pollutants in the air, water, and consumer products have been linked to higher rates of neurodevelopmental conditions. Reducing exposure when possible is beneficial.

Lead, Pesticides, and Chemical Exposures

Heavy metals, certain pesticides, and industrial chemicals like PCBs, BPA, and phthalates can disrupt neurological development.

Living Near High-Traffic or Industrial Areas

Air pollution is a key contributor to environmental risk. Living near high-traffic roads or industrial zones has been associated with higher ASD rates in some studies.

Secondhand Smoke Exposure

Exposure to tobacco smoke—during pregnancy or after birth—introduces harmful chemicals that can affect early brain development.

Household Chemicals and ASD Risk

Common household items can contain endocrine-disrupting chemicals. No single chemical causes autism, but reducing exposure can help lower overall risk.

And importantly, research has repeatedly shown that vaccines do not cause autism.

Gender Differences and Autism Risk

Boys are diagnosed more often than girls, but we now know that many girls are missed or diagnosed later because their symptoms often present differently.

Differences in Symptom Presentation

Girls may have fewer obvious repetitive behaviors, or their interests may appear socially typical. Many mask their social challenges, making them harder to identify.

Possible Biological Reasons for Gender Disparity

Some theories suggest girls may require more genetic or environmental factors before autism traits appear—a “female protective effect.” Hormonal and immune differences are also being studied.

Challenges in Diagnosing Girls with Autism

Because traditional diagnostic tools were shaped around boys, girls are often overlooked. Increased awareness continues to close this gap.

Vaccines and Autism: What Does Science Say?

Parents often ask me about vaccines, so I want to be direct and clear here.

Reviewing Scientific Evidence on Vaccines

Numerous large, high-quality studies across many countries show the same result: vaccines do not cause autism. Autism rates do not change with vaccine schedules, timing, or ingredients.

Common Vaccine Myths Debunked

Common myths—such as vaccines overwhelming the immune system—have been thoroughly disproven. Children encounter far more antigens in everyday life than in any vaccine.

Official Recommendations by Health Authorities

Organizations like the CDC and WHO strongly recommend routine childhood vaccinations based on decades of research confirming their safety.

How Immunization Programs Benefit Children

Vaccines prevent serious diseases and protect children with developing immune systems. They also support community immunity and help create healthier, safer environments for all children.

Epigenetic Factors and Gene-Environment Interactions

Epigenetics helps explain how genetics and environment interact—something I see reflected in research and in families' experiences.

What Are Epigenetic Changes?

Epigenetic changes influence whether certain genes turn on or off. These changes don’t alter DNA but can impact development.

Role of Environmental Influences on Genes

Environmental factors—nutrition, pollutants, medications—can shape epigenetic patterns related to brain development.

Ongoing Research in Epigenetics and ASD

Researchers are mapping specific epigenetic changes associated with ASD. Twin and genetic studies are especially helpful in advancing this work.

Implications for Prevention and Intervention

Understanding epigenetics may help refine early intervention and prevention strategies by focusing on modifiable influences that support children’s development.

Modifiable Risk Factors and Prevention Strategies

Not all risk factors can be changed, but some lifestyle and environmental adjustments can help support healthier development overall.

Maternal Nutrition and Supplementation

Nutrients like folic acid, omega-3s, and vitamin D play important roles during pregnancy. Proper nutrition supports fetal brain development.

Avoiding Harmful Environmental Exposures

Reducing exposure to pesticides, heavy metals, and endocrine-disrupting chemicals is one way families can support healthier outcomes.

Promoting Maternal Health and Mental Well-Being

Good prenatal care, chronic condition management, and emotional support all contribute to healthier early development.

Seeking Early Pediatric Care and Developmental Screening

Early developmental screenings allow providers to identify delays and support children as early as possible—something I advocate for with every family I work with.

Conclusion

Understanding autism risk factors isn’t about predicting outcomes—it’s about helping families feel informed and supported. The combination of genetics, prenatal environment, early childhood exposures, and developmental factors creates a complex picture, but knowledge allows us to approach care with confidence and compassion.

When families reach out to me with questions, I always emphasize that support matters far more than risk factors.Early intervention, a nurturing environment, and access to quality care make a meaningful difference in a child’s growth.

If you're looking for trusted ABA therapy services, I truly recommend exploring the team at Steady Strides ABA. We provide individualized ABA therapy across Texas and New Mexico, offering flexible service options to support your child where they learn best—including:

• Home-based ABA therapy
• School-based ABA therapy
• Center-based ABA therapy

Every child deserves a supportive path forward, and with the right tools and guidance, we can help make that journey steady, encouraging, and full of growth.

Frequently Asked Questions

Sources:



• https://www.ncbi.nlm.nih.gov/books/NBK573613/
• https://parisbraininstitute.org/disease-files/autism-spectrum-disorders/what-are-biological-mechanisms-and-causes-autism
• https://pmc.ncbi.nlm.nih.gov/articles/PMC5467975/
• https://academic.oup.com/eurpub/article/34/Supplement_3/ckae144.1324/7844750
• https://www.psychiatrist.com/jcp/autism-spectrum-disorder-1-genetic-and-environmental-risk-factors/
• https://publichealth.jhu.edu/2025/vaccines-do-not-cause-autism