According to Gram Research analysis, a study of 906 babies found that prenatal exposure to a combination of common chemicals (like BPA in plastics), air pollution, household mold, low folate intake, and reduced sunlight may silence a critical brain gene called aromatase by 0.71 units through DNA methylation. This gene helps balance hormones needed for normal brain development, and reduced activity is linked to autism risk, particularly in males.
A new study of over 900 babies found that pregnant people exposed to common chemicals like BPA (found in plastics), air pollution, and low folate levels may change how a specific brain gene works in their babies. This gene, called aromatase, helps balance hormones important for brain development. The research suggests that multiple environmental exposures during pregnancy can work together to affect this gene through a process called DNA methylation, which turns genes up or down without changing the DNA itself. This finding could help explain why some environmental factors are linked to autism risk.
Key Statistics
A 2026 study of 906 babies in the Barwon Infant Study found that prenatal exposure to a mixture of chemicals, air pollution, and nutritional factors increased methylation of the aromatase brain gene by 0.71 units (95% CI 0.11-1.32, p=0.021), potentially reducing brain hormone balance.
Bisphenols (including BPA), phthalates, household mold, low folate intake, reduced sunlight, and air pollution were identified as the top six prenatal exposures contributing to increased silencing of the aromatase gene in newborn cord blood.
Research shows that reduced aromatase activity in the brain is associated with increased autism symptoms in males, and this 2026 study identified DNA methylation of the aromatase gene as a biological mechanism through which multiple environmental factors may increase autism risk.
The Quick Take
- What they studied: Whether common pregnancy exposures (chemicals, air pollution, nutrients, sunlight) change how a brain gene called aromatase works in newborns
- Who participated: 906 babies and their mothers from the Barwon Infant Study in Australia, tracking exposures during pregnancy and measuring gene changes in cord blood at birth
- Key finding: Prenatal exposures to chemicals like BPA, phthalates, air pollution, household mold, and low folate were linked to increased methylation (silencing) of the aromatase gene, which could reduce brain hormone balance
- What it means for you: If you’re pregnant or planning pregnancy, reducing exposure to plastics, improving air quality, ensuring adequate folate intake, and getting sunlight may help protect your baby’s brain development. However, this is one study and more research is needed before making major changes.
The Research Details
Researchers followed 906 pregnant people and their babies in Australia as part of the Barwon Infant Study. They measured 25 different environmental exposures during pregnancy, including chemicals in plastics (BPA and phthalates), air pollution, medications, nutrition (especially folate), and sunlight exposure. At birth, they collected cord blood and tested whether these exposures had changed the aromatase gene through a process called DNA methylation, essentially checking if the gene was turned up or down.
Instead of looking at each exposure separately, the researchers used a special statistical method called Weighted Quantile Sum regression that examines how all 25 exposures work together as a mixture. This approach is more realistic because pregnant people are exposed to many things at once, not just one chemical or factor.
The researchers specifically looked at a part of the aromatase gene called the P1.f promoter, which is active in the brain. This is important because aromatase in the brain converts male hormones into female hormones that are crucial for normal brain development in all babies.
Most research on pregnancy and autism risk looks at one exposure at a time, but real life involves multiple exposures happening together. This study’s approach of examining the combined effect of many exposures is more realistic and may better explain why some babies develop autism. Additionally, identifying DNA methylation as the mechanism, the biological ‘how’ behind the risk, helps scientists understand what’s actually happening in the brain and could lead to better prevention strategies.
This study has several strengths: a large sample size (906 participants), measurement of many relevant exposures, and focus on a specific biological mechanism. However, it’s observational, meaning researchers measured what happened naturally rather than randomly assigning people to different exposures. The study was conducted in Australia, so findings may differ in other populations. The researchers measured exposures during pregnancy but only checked gene changes once at birth, so they couldn’t track changes over time.
What the Results Show
The combined mixture of all 25 prenatal exposures was significantly associated with increased methylation of the aromatase gene’s P1.f promoter. Specifically, the adjusted mean difference was 0.71 (95% confidence interval 0.11 to 1.32, p=0.021), meaning babies exposed to higher levels of this mixture showed more gene silencing.
Within the mixture, the exposures with the strongest individual contributions were bisphenols (including BPA), reduced sunlight exposure, household mold, phthalates, low folate intake, and air pollution. Notably, no single exposure dominated the effect, instead, multiple factors working together appeared to drive the change in gene methylation.
Increased methylation of this gene is concerning because it reduces aromatase activity in the brain. Aromatase converts androgens (male hormones) into neuroestrogens (brain-active female hormones) that are essential for normal brain development, including proper social and communication skills. Animal studies and human research have shown that reduced aromatase activity is associated with increased autism symptoms, particularly in males.
The study identified specific chemicals and factors that warrant attention: BPA and other bisphenols (chemicals in many plastics and food containers), phthalates (chemicals that make plastics flexible), household mold exposure, and inadequate folate intake all contributed to the methylation effect. Reduced sunlight exposure during pregnancy also played a role, suggesting that vitamin D or light exposure itself may be important for protecting this gene. Air pollution exposure rounded out the major contributors.
Previous research had shown that BPA alone could increase methylation of this same gene region, but this is the first study to systematically examine how BPA works alongside other environmental factors. The finding that multiple exposures contribute to the effect aligns with the ‘multiple hit’ theory of autism, the idea that autism develops when several risk factors combine rather than from a single cause. This study provides a specific biological mechanism (aromatase gene methylation) through which this multiple-hit process might occur.
The study measured exposures during pregnancy but only assessed gene methylation once at birth, so it’s unclear how methylation changes over time or whether it remains stable. The research is observational, meaning it shows association but cannot prove that these exposures directly cause the gene changes, other unmeasured factors could be responsible. The study was conducted in Australia with a specific population, so results may not apply equally to all geographic regions or ethnic groups. Additionally, while the study measured cord blood methylation, it didn’t measure actual aromatase enzyme activity or brain function, so the real-world impact on development remains to be determined.
The Bottom Line
Pregnant people should consider reducing plastic use (especially heating food in plastic containers), ensuring adequate folate intake through diet or supplements, minimizing air pollution exposure when possible, addressing household mold problems, and getting regular sunlight exposure. These recommendations align with general prenatal health guidance. However, this is one observational study, so these suggestions should be discussed with healthcare providers rather than viewed as definitive medical advice.
Pregnant people and those planning pregnancy should be aware of these findings. Parents of children with autism may find this research helpful for understanding potential causes. Healthcare providers, public health officials, and environmental policy makers should consider these results when developing prenatal health guidance and environmental regulations. People with genetic variations affecting aromatase may be particularly interested in these findings.
If these exposures do affect brain development, the critical period appears to be during pregnancy, as the study measured cord blood at birth. Changes in environmental exposures during pregnancy would theoretically need to occur before birth to prevent methylation changes. Long-term follow-up studies would be needed to determine whether methylation changes at birth predict autism diagnosis later in childhood.
Frequently Asked Questions
Can BPA in pregnancy cause autism?
BPA exposure during pregnancy may increase methylation of the aromatase gene, which is linked to autism risk, but this doesn’t mean BPA directly causes autism. Multiple environmental factors working together appear to influence this gene, and more research is needed to establish direct causation.
What should pregnant people do to protect their baby’s brain development?
Ensure adequate folate intake (400-800 mcg daily), reduce plastic container use especially for hot foods, get regular sunlight exposure, minimize air pollution exposure when possible, and address household mold problems. Discuss these strategies with your healthcare provider for personalized guidance.
Is low folate during pregnancy linked to autism?
This study found that low folate intake was one of the top six prenatal exposures associated with increased methylation of the aromatase gene, which is linked to autism risk. Adequate folate is important for many aspects of fetal brain development beyond this specific gene.
Does sunlight exposure during pregnancy matter for brain development?
This study found that reduced sunlight exposure during pregnancy was associated with increased silencing of the aromatase gene. Sunlight exposure may influence vitamin D production or have direct effects on gene regulation, though more research is needed to understand the mechanism.
Can you reverse DNA methylation changes that happen during pregnancy?
This study measured methylation at birth but didn’t track whether it changes over time. Some research suggests methylation can be modified, but it’s unclear whether prenatal methylation changes can be reversed after birth or whether they persist throughout life.
Want to Apply This Research?
- For pregnant users: Track daily folate intake (target 400-800 mcg), plastic container use (number of times heating food in plastic), sunlight exposure (minutes outdoors), and air quality index in your location. Log weekly household mold observations.
- Replace plastic food containers with glass or stainless steel, take a prenatal vitamin with folate, spend 15-30 minutes outdoors daily, and schedule mold inspection if living in damp environments. Track these changes in the app to monitor consistency.
- Create a weekly environmental exposure dashboard showing folate intake, plastic use reduction, sunlight minutes, and air quality exposure. Set reminders for vitamin intake and outdoor time. For users with children, note any developmental milestones to correlate with prenatal exposure data collected during pregnancy.
This research describes associations between prenatal environmental exposures and changes to a specific gene, but does not prove that these exposures directly cause autism or other developmental conditions. The study was conducted in one population and findings may not apply universally. Pregnant people should discuss any concerns about environmental exposures or prenatal health with their healthcare provider before making significant changes to diet, supplements, or lifestyle. This article is for educational purposes and should not replace professional medical advice. If you have concerns about your child’s development, consult with a pediatrician or developmental specialist.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
