Pregnant women living in greener neighborhoods show lower levels of chronic stress hormones, according to a study led by Bar-Ilan University that measured stress markers accumulated over several months.
Researchers found that greater vegetation exposure around the home during the second trimester was linked to lower concentrations of cortisol and cortisone, hormones involved in the body's stress response.
"Our findings suggest that exposure to greenery around the home is associated with reduced chronic stress hormones during pregnancy," Said Sohini Bhattacharya, a doctoral candidate at Bar-Ilan University's Azrieli Faculty of Medicine. "This is important because prolonged exposure to elevated stress hormones can negatively affect both the mother and the developing fetus."
Published in Environmental Epidemiology, the study examined 385 pregnant women recruited at the Helen Schneider Hospital for Women at Rabin Medical Center in Petah Tikvah. Women in greener environments during their second trimester had significantly lower hormone concentrations in their hair.
Hair samples provide a distinct advantage over blood, saliva or urine tests, which measure stress over brief periods. Hair analysis can record hormone levels spanning several months, allowing researchers to assess longer-term exposure. Both cortisol and cortisone play important roles in metabolism, immune function and sleep cycles, though persistently elevated levels have been associated with adverse health effects for mother and fetus.
The team assessed vegetation using satellite imagery and the Normalized Difference Vegetation Index, as well as Google Street View images to examine greenery from a pedestrian perspective and distinguish vegetation types. Results were consistent across both methods and varying distances from homes.
An unexpected finding involved grass. Women living in neighborhoods with greater visible grass had notably lower stress hormone levels than those in areas with less grass.
The lead researcher stated: "Our findings support efforts to preserve and expand green spaces and greenness in residential neighborhoods. As cities continue to grow around the world, integrating trees, grass and other vegetation into urban environments may provide a simple and accessible strategy for improving public health."
The research built on earlier work by the same team examining the first trimester, now expanding to include an additional hormone, the second trimester and more detailed assessment methods.