Bar-Ilan study links greener neighbourhoods to lower stress hormones in pregnancy

Pregnant women who live in greener neighbourhoods may carry less long-term stress, according to a study led by Bar-Ilan University's Azrieli Faculty of Medicine and published in the journal Environmental Epidemiology. JNS reported the findings on 19 July 2026.

The researchers, led by doctoral candidate Sohini Bhattacharya, studied 385 pregnant women at the Helen Schneider Hospital for Women at Rabin Medical Center in Petah Tikva. Instead of relying on questionnaires or on blood, saliva or urine tests, which reflect stress over hours or days, they measured the stress hormones cortisol and cortisone in hair samples taken during the second trimester. Hair accumulates these hormones as it grows, providing a record that covers several months. They then compared the results with how much vegetation surrounded each woman's home, using both satellite imagery and ground-level measures.

Women with more greenery around their homes during the second trimester had significantly lower concentrations of both hormones. The pattern held across several ways of measuring greenery and across different distances from the home. The authors caution that the study shows an association, not proof that plants and parks directly lower stress, but it adds to a growing body of evidence that access to nature benefits health. Because hair-based measures capture months rather than moments, the study avoids some of the noise that has weakened earlier research relying on self-reported stress.

Persistently high levels of stress hormones during pregnancy have been linked to harmful effects for both mother and baby, which is why the researchers see the result as relevant to urban planning and public-health policy as well as to individual families.