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A new study published in Developmental Science provides evidence that household income instability during pregnancy may be linked to differences in the developing brain. The researchers found that infants whose families experienced sudden income losses during the prenatal period tended to have smaller volumes in brain regions involved in stress regulation and emotional processing.
The study highlights the possibility that fluctuations in financial stability — rather than income level alone — can shape early neural development. The findings add to growing evidence suggesting that the stress associated with unpredictable life conditions may affect the developing brain as early as infancy.
“Previous work has found that living in poverty is widely associated with poorer outcomes in parents and children. Despite the fact that many families experience frequent changes in income, researchers rarely examine these changes directly,” said study author Genevieve Patterson, a graduate student in the Family and Child Neuroscience Lab at the University of Denver.
“While doing interviews with families as part of this project, I observed that pregnancy and postpartum are times when families are particularly vulnerable to changes in income (e.g., stopping work due to pregnancy complications, lack of available parental leave), and that this can be very stressful. This was also consistent with my observations from outside of the lab. Given that prenatal stress has been associated with infant development, we decided to explore whether prenatal income instability is a stressor associated with infant brain outcomes after birth.”
The study was part of a larger longitudinal research project focused on the developmental effects of early life experiences. A total of 63 infants and their birthing parents were recruited from obstetrics and gynecology clinics in the Denver area. The research team deliberately oversampled low- and middle-income families in order to capture a range of financial experiences during pregnancy.
To track household income over time, researchers conducted detailed interviews at multiple points during pregnancy. They collected information about monthly income from employment and other sources and calculated both the average income-to-needs ratio and month-to-month changes. A significant income loss, or “negative income shock,” was defined as a decrease of at least 25% in household earnings from one month to the next.
After birth, the infants underwent a magnetic resonance imaging (MRI) scan while sleeping. The scans measured the size of two brain regions: the hippocampus, which plays a role in memory and stress regulation, and the amygdala, which is involved in emotional processing and fear responses. Both regions have been shown in past research to be sensitive to stress exposure during development.
Nearly half of the families in the study experienced at least one significant drop in income during pregnancy. These negative income shocks were more common among lower-income families but occurred across the entire income range of the sample.
The researchers found that a higher number of income losses during pregnancy was associated with smaller volumes in the right hippocampus and right amygdala in infants. These associations held even after accounting for factors such as birthweight, the infant’s age at the time of the scan, and overall brain size. The effect sizes were modest but statistically significant, indicating a consistent pattern in the data.
The findings also indicated that parents who experienced more negative income shocks reported higher levels of anxiety and depression during pregnancy. These psychological symptoms were also related to smaller hippocampal and amygdala volumes in their infants, raising the possibility that stress-related changes in the parent could play a role in shaping early brain development.
“Instability in income, specifically month-to-month income losses, can be a significant stressor, especially during critical periods like pregnancy,” Patterson told PsyPost. “Stress during this time can have impacts on two generations — parents and infants. Therefore, income instability is an important factor to consider in the development of public policy. Programs can best support families by providing stable sources of reliable income during pregnancy and postpartum.”
The authors suggest that unpredictability in income could create a psychological burden. Financial instability may increase uncertainty, limit planning, and reduce perceived control — all of which can contribute to chronic stress. These stressors, in turn, may influence biological processes such as hormone levels, immune function, or inflammation, which can affect the developing brain.
Interestingly, the study did not find significant links between average income levels and the size of these brain regions. Nor were positive income changes — unexpected gains — associated with differences in brain structure. This suggests that it may not be financial hardship in general, but rather the stress of losing income, that influences brain development in these specific areas.
“We were surprised that the number of significant monthly income losses significantly predicted infant brain volumes but not income-to-needs ratio (a more general measure of household resources),” Patterson said. “There may be something uniquely stressful about instability and income loss that is important for future researchers to consider. However, it is also important to note that monthly income losses are more common in families with lower incomes. Future research with larger samples is needed to help disentangle the relationships between income instability, overall income, and infant outcomes.”
As with all research, there are some limitations. The study was correlational, meaning it cannot establish causality between income loss and changes in brain development.
“We want to remind readers that while we found an interesting association with important policy implications, the design of our study cannot prove that income shocks caused differences in brain development, and there are many interacting factors that influence both parent stress and infant brain development,” Patterson said. “We are planning to explore these relationships in other periods (e.g., later in childhood) to further develop our understanding of the role of income instability in child development.”
The study, “Prenatal Household Income Instability and Infant Subcortical Brain Volumes,” was authored by Genevieve Patterson, Alexander J. Dufford, Taryn W. Morrissey, Martin Styner, Sun Hyung Kim, and Pilyoung Kim.