An international study has revealed that living in neighborhoods with extensive green spaces may help reduce chronic stress levels in pregnant women, positively impacting the health of both mother and fetus.

The researchers, including participants from the Alfred Wegener Institute in Germany, explained that the study provides evidence that the residential environment can affect the health of pregnant women, not just their psychological well-being. The results were published Monday in the journal Environmental Epidemiology.

Chronic stress during pregnancy is one of the factors that can negatively affect the health of the mother and fetus, as persistently elevated stress hormones such as cortisol and cortisone increase the risk of certain pregnancy complications and may affect fetal growth and development. These two hormones play a key role in regulating vital processes such as metabolism, immune system functions, and sleep cycles, but prolonged elevation of their levels can disrupt the balance of these functions, making stress reduction during pregnancy important for maintaining the health of both mother and child.

The researchers analyzed hair samples from 385 women during the second trimester of pregnancy to measure concentrations of cortisol and cortisone. This method is more accurate for assessing long-term stress because it reflects hormone accumulation over several months, unlike blood, saliva, or urine tests that measure stress levels over a short period.

The results showed that women living in areas with more green spaces around their homes had significantly lower levels of cortisol and cortisone compared to those living in areas with fewer green spaces.

To verify the results, the researchers used two different methods to estimate the amount of green space around the participants' homes. The first method relied on satellite imagery using the Normalized Difference Vegetation Index (NDVI), one of the most commonly used indicators for measuring vegetation density. The second method used Google Street View images to assess the green environment from street level, allowing researchers to distinguish between trees, grass, and other plants from a pedestrian perspective. Both methods confirmed the same result: increased green space was associated with lower levels of chronic stress hormones.

One of the study's key findings was that a higher proportion of green grass around homes was associated with a clear decrease in cortisol and cortisone levels, compared to areas with less grass.

According to the researchers, this finding has practical significance for urban planners and policymakers, as it suggests that increasing grassy areas could be a low-cost way to improve public health and psychological well-being.

They added that the findings support efforts to preserve and expand green spaces in residential neighborhoods, noting that integrating trees, grass, and plants into cities could be a simple and accessible way to promote public health, especially amid increasing pressures from armed conflicts, climate change, and urban expansion.