Study shows stress is hereditary

Children may be less resilient to stress if their mothers suffered stress in their second trimester of pregnancy, new research suggests. 

The small study by the University of California at San Francisco found babies of mothers with the highest number of stressful life events were more reactive to stressors, and took longer to recover.

This stress appeared to impact their heart, and put them at a higher risk of depression and behavioral issues in later life than their peers. 

It comes just weeks after another study suggested male stress could affect the resilience of their offspring, building on a growing swell of research connecting generational stress levels. 

The study by the University of California San Francisco found babies of mothers who had the most stressful life events were more reactive to stressors and took longer to recover

The study by the University of California San Francisco found babies of mothers who had the most stressful life events were more reactive to stressors and took longer to recover

The study by the University of California San Francisco found babies of mothers who had the most stressful life events were more reactive to stressors and took longer to recover

‘This isn’t automatically good or bad, but we know that being highly reactive places children at risk for a range of psychopathological problems,’ explained first author Dr Nicole Bush of the university’s Psychiatry and Pediatrics department. 

In particular, she said, children are at risk of ‘anxiety and depression, as well as externalizing problems, such as disruptive behavior, especially if they experience adverse family and school environments.’

To ascertain whether stress during pregnancy could have a knock-on effect, Bush and her team looked at the stress levels of 151 low-to-middle-income women who were between 12 and 24 weeks pregnant. 

They tracked each woman through their first, second and third trimesters, then for six months after giving birth. 

At regular intervals during pregnancy, they measured the mothers’ stress levels using a questionnaire, which documented stressful events such as illness, housing issues, legal issues, family problems, and relationship problems. 

Then, when the babies reached six months, they monitored the babies’ hearts to measure their reactive stress levels.

The 22 women with the most stressors in their lives had far more reactive children. 

These children were 22 percent more ‘reactive’ than the babies of the 22 women who reported the lowest levels of stress. 

Dr Bush warns this increased reactivity can put significant strain on the heart, that has an impact on their behavior and health for life. 

It is an indicator of a dulled down ‘parasympathetic’ nervous system, which is responsible for conserving energy and slowing the heart rate down after a shock or stress. It is also important for resting the body to keep it in good health, and for digesting food.  

According to the researchers, despite the apparent hereditary aspect, parents could try to alleviate their child’s heightened stress by ensuring a soothing environment in their first few months. 

In a soothing environment, kids ‘don’t have their stress response triggered too often,’ she says.

She adds that, in this scenario, they may even ‘exhibit better-than-average social skills and emotional and behavioral well-being, because greater reactivity can make them more sensitive to the benefits of positive relationships and experiences in their environments. 

‘At this point, we don’t know the lifelong impact of higher reactivity and lower surgency and self-regulation for these babies,’ Bush explained.

‘A lot will depend on other factors, such as families and communities. 

‘Providing healthy environments postnatally could buffer the negative impact of high reactivity and lower surgency and self-regulation.’ 

The study was published in the journal Development and Psychopathology. 

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