Green Environment and Pregnancy Stress: Findings from a New Study
A new study led by researchers from Bar-Ilan University found that pregnant women living in greener neighborhoods may have lower levels of long-term stress. The study showed that greater exposure to residential greenery during pregnancy was associated with lower levels of cortisol and cortisone—two key stress hormones that affect both maternal and fetal health.
Hair Hormones: A Record of Chronic Stress
Unlike stress hormones measured in blood, saliva, or urine, which reflect stress over minutes or hours, hormones in hair provide a profile accumulated over several months. By analyzing hair samples from hundreds of pregnant women, researchers assessed chronic stress levels during the second trimester.
Key Results: More Greenery, Lower Stress Hormones
Published in Environmental Epidemiology, the study found that women living in greener environments during their second trimester had significantly lower concentrations of cortisol and cortisone in their hair. The findings were consistent across several measures of residential greenery and different distances from homes.
From Sky to Street: Two Methods to Measure Greenery
The team used two complementary approaches: satellite imagery with the Normalized Difference Vegetation Index (NDVI), and a novel method based on Google Street View images to assess greenery from a pedestrian perspective, distinguishing grass, trees, and other plants. Both methods pointed to the same conclusion: greener surroundings are linked to lower chronic stress hormone levels.
Surprising Finding: The Role of Grass
Street-level analysis revealed that women living in areas with a higher percentage of grass around their homes had notably lower cortisol and cortisone levels than those in less grassy environments. This finding may have practical implications for urban planners seeking cost-effective public health strategies.
Stress Hormones and Pregnancy Health
Cortisol and cortisone play important roles in regulating metabolism, immune function, sleep cycles, and maintaining pregnancy. However, prolonged elevation can harm both mother and fetus. Previous studies relied on self-reported measures or short-term indicators, while this study used hair samples to assess long-term stress, filling a critical gap.
Implications and Future Research
Lead researcher Prof. Keren Agay-Shay stated, 'Our findings support efforts to preserve and expand green spaces in residential neighborhoods. As cities grow, integrating trees, grass, and other vegetation into urban environments may provide a simple and accessible strategy for improving public health.' The team is continuing to investigate environmental factors like air pollution and temperature that may affect hormone levels during pregnancy.
The Xiaoshu Health App can sync with Apple Health to track related indicators, helping you record stress levels, sleep quality, and other health data, making green living and health management more connected.