Researchers have found that pregnant people living in neighborhoods with more greenery have measurably lower levels of chronic stress hormones. The study adds to a growing body of evidence that everyday exposure to nature may help with stress resilience during pregnancy.
The study enrolled 385 pregnant people and collected hair samples during the second trimester. Researchers tested the samples for four hormones: cortisol, cortisone, progesterone, and DHEA. Hair is useful for this type of research because it reflects long-term hormonal patterns over weeks and months, rather than a single moment in time.
To measure greenness, the team used two methods. Satellite imagery captured all vegetation within 100, 300, and 500 meters of each person’s home. Google Street View images, analyzed by deep learning algorithms, estimated what percentage of the street-level view was green. This gave researchers both a bird’s-eye view and a ground-level perspective.
Pregnant people in the greenest neighborhoods had lower hair cortisol levels than those in the least-green areas. This finding held up 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 home. At street level, neighborhoods with more grass coverage were associated with lower levels of both cortisol and cortisone. The cortisol finding was not limited to a single point in pregnancy. When researchers looked at cortisol across both the first and second trimesters, the same relationship appeared: more greenery, lower cortisol.
Pregnancy is one of the most physically and emotionally demanding periods of life. Chronic stress raises the stakes. Elevated stress hormones during pregnancy have been linked to a higher risk of adverse outcomes for both the pregnant person and the developing baby. This refers to stress that builds over weeks and months, not occasional hard days.
Cortisol is the body’s primary stress hormone. The research aligns with Stress Reduction Theory, which suggests that natural environments trigger an evolutionary calm response. This dials down the hormonal cascade that follows psychological stress. The study was conducted in one city, so more work is needed, but the direction is clear.
Small, consistent doses of nature exposure may be what matters most. Spending time in nearby parks or green spaces, even brief regular visits, can increase everyday nature exposure without requiring a major time commitment. Taking walks along tree-lined or grassy routes may make a difference over time. Green micro-moments, such as a garden, a grassy median, or a tree-filled courtyard, also count. The goal is consistent, ambient exposure to natural environments throughout the week.
Broader context on stress and pregnancy
Chronic stress during pregnancy has been a topic of increasing research. Studies have linked high stress levels to preterm birth, low birth weight, and developmental issues in children. Stress hormones like cortisol can cross the placenta, potentially affecting fetal development. While this study did not measure birth outcomes, it adds to the understanding of how the environment may influence stress physiology during pregnancy.
Other research has shown that access to green spaces is associated with better mental health outcomes in the general population. Studies have found lower rates of depression, anxiety, and perceived stress among people living near parks or wooded areas. The mechanisms are not fully understood, but theories include reduced air pollution, increased physical activity, and the calming effects of natural scenes.
The findings suggest that urban planning and housing policy could play a role in maternal health. Ensuring that residential areas have adequate green space may be a low-cost way to support public health. For individuals, the study offers a practical takeaway: even small amounts of nature exposure may help manage stress during pregnancy.
