Babies learn through everyday interactions with their caregivers. By watching, listening, communicating, and most importantly playing. In the first year of life, key neural connections are emerging in the context of these warm, predictable, and responsive social interactions between the infant and caregiver (Scott & Brito, 2022).
But the period after childbirth is also often a vulnerable and stressful time for parents. Mothers routinely face post-birth complications, lactation difficulties, sleep deprivation, and chronic stress. The COVID-19 pandemic has only exasperated these difficulties, and prevalence rates of perinatal depression and anxiety have increased significantly over the last two years (Shuffrey, Thomason, & Brito, 2022). Stress is a common experience for all caregivers, but high levels of chronic stress can potentially disrupt a caregiver’s ability to respond to their infants’ cues in a sensitive and timely manner.
Infant Studies of Language and Neurocognitive Development Lab at NYU
One way to decrease maternal stress here in the United States may be through the implementation of paid parental leave. The U.S. is one of a handful of countries in the world without a national policy mandating paid leave after childbirth. Currently, only 19% of caregivers in the U.S. have access to paid leave, forcing caregivers to return to work within weeks of giving birth or take unpaid leave. Black and Hispanic mothers are even less likely to have access to paid leave compared to White mothers. Mandating paid leave could potentially lead to reductions in health disparities, as paid leave has been associated with lower likelihood of postpartum depression, increases in breastfeeding, and more secure attachment between mother and child (Jou et al., 2018).
Previous work from my lab found that in a sample of over 300 families, mothers who took paid leave had toddlers with higher language scores than children whose mothers took unpaid leave. And this was true even after accounting for important indicators like household income and maternal education. We also found that paid leave was linked to fewer socio-emotional problems during toddlerhood, specifically for mothers with lower levels of education (Kozak et al., 2021).
In a newer study published this past year, we wanted to extend this finding and examine if different experiences of leave after birth would be linked to variations in infant brain function. In a sample of about 80 socio-demographically diverse families with 3-month-old infants from New York City, we recorded infant brain activity using electroencephalography (EEG), took a hair sample from the mom to measure physiological stress indexed by cortisol, and also had dyads engage in a 5-minute free play.
We observed three important findings. First, compared to infants whose mothers had unpaid leave, infants whose mothers took paid leave were more likely to demonstrate an EEG activation profile that may reflect a more mature pattern of brain function. Second, we found that mothers with paid leave had lower levels of physiological stress. And lastly, we observed that mothers with paid leave showed higher levels of sensitivity and responsiveness with their infants during the free-play interaction (Brito et al., 2022).
So, what does this tell us? Experiences of paid leave may reflect an economically stable period of bonding needed for dyads to foster sensitive, reciprocal interactions where there is less stress and worry hindering these experiences. This study adds to the abundance of evidence across an array of fields suggesting that increasing access to paid leave is related to a wide range of benefits for families and could help mitigate inequities in developmental outcomes.
References
Brito, N. H., Werchan, D., Brandes‐Aitken, A., Yoshikawa, H., Greaves, A., & Zhang, M. (2021). Paid maternal leave is associated with infant brain function at 3 months of age. Child Development. https://doi.org/10.1111/cdev.13765opens in new window
Jou, J., Kozhimannil, K. B., Abraham, J. M., Blewett, L. A., & McGovern, P. M. (2018). Paid maternity leave in the United States: associations with maternal and infant health. Maternal and Child Health Journal, 22(2), 216–225.
Kozak, K., Greaves, A., Waldfogel, J., Angal, J., Elliott, A. J., Fifier, W. P., & Brito, N. H. (2021). Paid maternal leave is associated with better language and socioemotional outcomes during toddlerhood. Infancy, 26(4), 536–550.
Scott, L. S., & Brito, N. H. (2022). Supporting Healthy Brain and Behavioral Development During Infancy. Policy Insights from the Behavioral and Brain Sciences, 9(1), 129–136.
Shuffrey, L. C., Thomason, M. E., & Brito, N. H. (2022). Improving Perinatal Maternal Mental Health Starts with Addressing Structural Inequities. JAMA psychiatry.