January 9, 2018
We have long known that environmental toxins can have an adverse impact on pregnant mothers and their infants, but it turns out the environment can have a subtler impact than once thought. Chronic, pronounced stress during pregnancy impacts a baby’s brain development in ways that can negatively affect attention, self-control, and behavior for years to come. That kind of stress is more commonly experienced by people living in poverty, and may help to explain the notoriously thorny cycle of poverty, explain Lisa Gatzke-Kopp and Kristine Creavey in a review for Policy Insights from the Behavioral and Brain Sciences. Stress impairs development and biologically predisposes children to experience later stress, making it increasingly difficult to break the cycle of disadvantage. To end that cycle, the authors write, we need to invest in prevention and intervention programs during the prenatal period. The title of their article, “Unsealing Fate,” illuminates how urgent that need is for children and society.
“For the 9 months of gestational development, the mother is the environment,” Gatzke-Kopp and Creavey point out. During that time, there are two types of environmental influences that can reach the unborn child: external influences like lead and nicotine that pass through the placenta, and conditions that originate within the mother like infection. Among the latter, stress is one of the most detrimental but difficult to measure. Chronic stress initiates a “developmental cascade” in a brain circuit known as the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the secretion of hormones involved in emotion, cognition, and behavior. High levels of stress lead the body to release higher-than-normal levels of cortisol. Moderate levels of that hormone help us activate our “fight or flight” response when necessary, but too much cortisol puts the body on constant alert, at the same time decreasing the ability to focus, think clearly, stay calm, and handle challenges. Negative effects can be seen as early as infancy and may persist throughout life in the form of anxiety, depression, hyperactivity, and aggression, and they also include atypical glucose metabolism that can increase the child’s risk for obesity.
In a cruel irony, those kinds of problems make it more difficult for children to succeed in school, get along with peers, and thrive in ways that pave a path out of poverty. It is a sad fact that “stress itself may be inherited from one generation to the next,” according to the authors, because stress during pregnancy can cause increased secretion of cortisol in the child not just in utero but for up to 10 years. And if those children grow up to be poor themselves and lack adequate transportation, safe housing, and well-resourced schools, they may end up “recreating the same environmental exposure for their own children.”
That doesn’t mean poverty is a hopeless condition, however, Gatzke-Kopp and Creavey are careful to point out. “Better understanding these mechanisms need not stigmatize, but rather illuminates fruitful targets for programs aimed at reducing poverty,” they explain.
Gatzke-Kopp and Creavey call for more public investment in programs to help break the poverty-stress-neurodevelopmental cycle, emphasizing the fact that low-income families are “disproportionately burdened with these additional risk pathways relative to higher SES families.” Some programs for pregnant women and very young children are beginning to make a difference. They include nurses or other trained professionals providing home visits with support and information to at-risk expectant mothers to reduce stress, and the Early Head Start program to boost cognitive stimulation in children ages 0-3. The authors suggest that other programs like the WIC nutritional program could be broadened to focus on stress and emotional well-being and that public health efforts also target reductions in environmental toxins like lead and nicotine that are more prevalent in the homes and communities of poor families. Even those who don’t partake in smoking and other risky behaviors themselves often have residual exposure, because they tend to have less choice in their housing, move frequently, and live near people who engage in risky behaviors to cope with the stresses of poverty. Creating the conditions that enable vulnerable mothers to make healthy, stable lives for their children could pay off in a relatively short period of time, and benefit society as a whole.
Drawn from “Unsealing Fate: Policy Practices Aimed at Reducing the Intergenerational Transmission of Poverty” by Lisa M. Gatzke-Kopp and Kristine L. Creavey in Policy Insights from the Behavioral and Brain Sciences.