Living Near Green Areas Protects The Developing Brain

Studies show that living close to nature, such as parks and green spaces, can help children develop their brains healthily. Researchers analyzed more than 1.8 million mothers and children in the US and found that exposure to green spaces before, during, and after pregnancy is associated with a lower risk of autism, ADHD, learning disabilities, and other disorders. The positive effects were even greater in children from low-income families and those living in cities.

Neurodevelopmental disorders, such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), have become increasingly common among children and are a major public health concern. These disorders affect brain development, which can hinder communication, socialization, speech, and behavior control.

Today, an estimated one in 36 children in the United States has autism, and one in 10 is diagnosed with ADHD. The number of cases has increased over the years, putting pressure on health, education, and social services systems.

Science already knows that many factors can contribute to these disorders, such as genetics, maternal health, air pollution, and exposure to chemicals during pregnancy. However, little is known about the impact of something seemingly simple and accessible: contact with nature.

Being near green spaces, such as parks and gardens, can bring benefits to mental and physical health. This applies to both pregnant women and children, and can have an impact even before pregnancy begins, that is, during the period when women are still planning to have children.

Why study this? Most previous studies have focused only on contact with nature during pregnancy or in the early years of a child's life. But now, scientists want to understand whether exposure to green spaces can also have positive effects even before pregnancy.

The idea is that contact with natural environments can reduce stress, improve the mental health of the expectant mother, and thus influence the healthy development of the baby. Furthermore, green spaces can improve air quality and reduce exposure to toxic substances in the environment, such as pollutants and pesticides, which are known to negatively affect brain development.

Researchers at the Harvard T.H. Chan School of Public Health in the USA analyzed data from more than 1.8 million mothers and children covered by the Medicaid program in the United States, which primarily covers low-income families.

They observed where these mothers lived and how much vegetation was in the surrounding area, using satellite imagery to calculate the "greenness" of each area. The analysis considered three key time points: before pregnancy, during pregnancy, and after birth.

The study followed these children for up to 14 years to determine whether they had neurodevelopmental disorders, such as autism, ADHD, learning disabilities, speech problems, or intellectual disabilities.

The study found very promising results. Children who were more exposed to green spaces during these critical periods had a lower risk of developing several disorders. For example, contact with nature before pregnancy was linked to a lower risk of intellectual disability.

During pregnancy, being near green spaces was associated with a lower risk of autism, and after birth, exposure to natural spaces helped reduce the risk of learning disabilities. These benefits were even stronger for Black and Hispanic children, and those living in urban areas.

This study shows that living near green spaces can be a protective factor for healthy brain development in children. This is especially important for communities with fewer resources, where environmental risks are often greater.

Improving access to green spaces can be a simple, natural, and effective way to support children's mental health and prevent neurodevelopmental disorders.

The research was funded by the U.S. National Institute of Environmental Health Sciences. The results reinforce the importance of public policies that encourage the creation and preservation of green spaces, especially in poorer and urban neighborhoods, as a strategy for promoting health from the beginning of life, or even before it begins.

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Preconception, prenatal and early childhood exposure to green space and risk of neurodevelopmental delays: a national cohort study among Medicaid enrollees

Hayon Michelle Choi, Krista F. Huybrechts, Sonia Hernandez-Diaz, Xinye Qiu, Michael Leung, Peter James, Matthew Shupler, Wanyu Huang, Yaguang Wei, Antonella Zanobetti, Christopher J McDougle, Joel Schwartz, Brent Coull, Marc Weisskopf, and Stefania Papatheodorou 

Environment International, Volume 202, August 2025, 109666

https://doi.org/10.1016/j.envint.2025.109666

Abstract: 

Exposure to green space is associated with children’s mental health, but its impact on neurodevelopment has been underexplored, especially in socioeconomically disadvantaged populations. This study examined the link between exposure to green space before, during, and after pregnancy and neurodevelopmental delays in children enrolled in Medicaid. This cohort study of 1,841,915 mother–child pairs used data from the Medicaid Analytic Extract (MAX) from 2001 to 2014, with up to 14 years of follow-up. The population of pregnant women enrolled in Medicaid is characterized by younger age, racial and ethnic diversity, lower income levels, and includes individuals with disabilities. Green space exposure was measured using the Normalized Difference Vegetation Index (NDVI) at the maternal residential zip code level. We examined exposure to green space during the preconception, prenatal, and postnatal periods to capture critical developmental windows both separately and with mutual adjustment. Neurodevelopmental outcomes were identified using validated algorithms and included autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), learning disabilities, speech and language disorders, coordination disorders, intellectual disabilities, and behavioral disorders. We applied a stratified Cox model accounting for individual and area-level confounders and examined effect measure modification by urbanicity, child’s race/ethnicity, and sex. The study found protective associations between green space exposure and most neurodevelopmental disorders. The strongest associations were seen for preconception exposure and intellectual disability (HR 0.66 [95 % CI: 0.48–0.95]), pregnancy exposure and ASD (HR 0.83 [95 % CI: 0.73–0.95]), and postnatal exposure for learning difficulties (HR 0.81 [95 % CI: 0.68–0.97]) per interquartile range (IQR = 0.12) increase in NDVI. The protective effects were stronger for Black/Hispanic children and for those living in urban areas. Green space exposure could benefit the children’s neurodevelopment, with more significant benefits for the Black and Hispanic populations. National Institute of Environmental Health Sciences R01-ES034038.