New research suggests that the amount of greenery near a pregnant person’s home may be linked to lower levels of chronic stress hormones. The study, published in a health journal, adds to the evidence that nature exposure could support stress resilience during pregnancy.
Researchers enrolled 385 pregnant people and collected hair samples during their second trimester. Hair samples were used because they reflect long-term hormone patterns, providing a view of chronic stress over weeks and months, rather than a single moment. The samples were tested for four hormones: cortisol, cortisone, progesterone, and DHEA.
To measure the amount of green space, the team used two methods. First, satellite imagery captured all vegetation within 100, 300, and 500 meters of each participant’s home. Second, Google Street View images were analyzed by deep learning algorithms to estimate the percentage of green space visible at street level. This combination provided both a bird’s-eye and a ground-level view of the neighborhood.
Key findings on stress hormones
The study found that pregnant people living in the greenest neighborhoods had lower hair cortisol levels compared to those in the least-green areas. This finding held even after researchers accounted for factors like neighborhood income and whether the location was urban or rural.
The link with cortisone was more specific. It appeared for greenness measured within a roughly 500-meter radius of the home. At street level, neighborhoods with more grass coverage were associated with lower levels of both cortisol and cortisone. The relationship between greenery and lower cortisol was not limited to one point in pregnancy. When researchers looked at cortisol levels across both the first and second trimesters, the same pattern appeared.
Why this matters
Pregnancy is a physically and emotionally demanding time. Chronic stress, which builds over weeks and months, has been linked to a higher risk of adverse outcomes for both the pregnant person and the developing baby. Cortisol is the body’s primary stress hormone. The research aligns with Stress Reduction Theory, which suggests that natural environments trigger a calming response, reducing the hormonal cascade that follows psychological stress. The study was conducted in one city, so more research is needed to confirm the findings.
Practical steps for more green exposure
The researchers noted that people do not need to move to a new neighborhood to benefit from the findings. Small, consistent doses of nature exposure may be most important. The following actions were suggested:
Spend time in nearby parks or green spaces. Even brief, regular visits to a local park can increase everyday nature exposure without a major time commitment. Take walks along tree-lined or grassy routes. Choosing a route with more greenery, even a street with mature trees, may make a difference over time. Look for green micro-moments, such as a garden, a grassy median, or a tree-filled courtyard. The goal is consistent, ambient exposure to natural environments throughout the week.
