New moms at risk of experiencing “baby blues” after childbirth tend to display a different pattern of brain activity compared to mothers who are not afflicted by the condition, according to new research published in PLOS One. The new findings indicate that mothers’ neural responsiveness to their infants’ emotional expressions is associated with the development of postpartum depression and anxiety.
Previous brain imaging research has suggested that postpartum depression and anxiety are distinct from other mood disorders, such as major depressive disorder, but there is still much to learn about the underlying neurobiology of the conditions.
“As mammals that invest a lot of time and energy raising our young, our brains have evolved some very intricate machinery to make sure we’re able to recognize and respond to a baby’s needs as well as have the motivation to engage in those caregiving behaviors even when it comes at a cost,” said study author Megan Finnegan, graduate student and a member of the PRISM Lab at the University of Illinois at Urbana-Champaign.
“Think about how hard it is to sleep when a baby’s crying and how good it can feel when the baby is smiling and laughing. When women experience postpartum depression, the typical brain responses to infants change in characteristic ways.”
“Yet, as disruptive as depression can be to both mother and baby, postpartum anxiety is also a surprisingly common occurrence. In fact, epidemiologic research suggests that comorbid postpartum depression and anxiety may be more common than experiencing only one or the other alone,” Finnegan explained.
“This aligns with what is known about depression and anxiety disorders more broadly in that they tend to occur together quite frequently. Thus, we decided that we also needed to look at how the brain differences were related to anxiety and examine the potential overlap in brain regions that may indicate a common component of emotional distress that may underlie both.”
The researchers used functional magnetic resonance imaging to monitor the brain activity of mothers as they viewed videos of their 3-month-old infant completing tasks evoking positive or negative emotion. In the positive emotion condition, the mothers viewed a video of their infant playing “peekaboo.” In the negative emotion condition, the mothers viewed a video of a their infant’s arms being gently held down to their sides — a situation known to provoke frustration. The mothers then completed follow-up assessments at 6, 12, and 18-months postpartum.
“What we didn’t know was whether differences in maternal brain response could be attributed to past experience with mental illness, potentially through long lasting changes to neural function following illness or perhaps, through a pre-existing predisposition to experience depression. Alternatively, how a mother’s brain is responding to her infant could be a sign of a broader trajectory of distress that without intervention, leads to a worsening symptom profiles later,” Finnegan said.
“To test this, we decided to look at how the ability of a mother’s brain to respond differently to her infant in pleasant (playing peek-a-boo) compared to unpleasant (crying) situations was related to symptoms of past, current, and future depression.”
Mothers who displayed greater neural activation to positive than negative videos tended to experience less subsequent depressive symptoms and anxiety. In contrast, the development of depressive symptoms and anxiety was more common among mothers whose neural responses to positive and negative videos were more similar.
Rather than being less responsive to positive videos, however, mothers who later reported greater postpartum symptoms tended to be more responsive to negative videos compared to mothers who later reported less symptoms. The finding suggests that “sensitization to negative emotional contexts” involving their infants might play a role in postpartum depression and anxiety.
“This research shows that differences in the way a mother’s brain responds to her infant’s cries and smiles is associated with the development of postpartum depression and anxiety symptoms almost a year later,” Finnegan told PsyPost.
“Conversely, there was very little evidence of the influence of past depression and anxiety on how mother’s brains responded to their babies. This indicates that rather than being a symptom of recurrent mental illness, current postpartum brain response may be part of a larger trajectory of symptom worsening. These findings would mean that reshaping the way in which women respond to their infants’ emotions could be a fruitful avenue for interrupting the course of postpartum depression and anxiety.”
Finnegan and her colleagues also found that elevated postpartum symptoms were not associated with the mothers’ self-reported emotional response to the videos or their assessment of their infant’s emotions. “That is, mothers did not necessarily think their baby was more negative in these situations, but rather, their brains responded differently to viewing their babies,” the researchers wrote. “This dissociation from conscious appraisal of their infant’s or their own emotions highlights the importance of considering brain measures to detect underlying response biases that may help drive postpartum psychopathology.”
But the study, like all research, is not without some limitations. For instance, only 24 mothers were included in the study.
“This is the first study to look at how fMRI measures are related to the development of future postpartum depression and anxiety. The work was conducted with a modest number of participants and it is essential that this work be replicated in larger and diverse cohorts to more accurately characterize the boundaries of brain tissue involved in this phenomenon,” Finnegan explained.
“For statistical reasons, we also had to examine the relationship of depression and anxiety in separate models and compare the overlap in qualitative terms. Future work could improve upon this by extracting the shared components of anxiety and depression scores to estimate levels of what psychologists call internalizing distress. Understanding how internalizing distress relates to changes in a mother’s brain response to her child may help us better describe and predict the evolution of postpartum affective disorders over the course of mother-child development.”
Finnegan herself became a mother during the course of the study. “This study began with a group of mothers of 3-month-old infants,” she remarked. “By the time this paper was accepted, I had become the mother of my first child who had just turned 3-months-old!”
“Also, although there is growing interest among psychologists to develop depression and anxiety treatments for the unique needs of postpartum women, for those currently experiencing distressing symptoms, Postpartum Support International is a valuable resource for readers to be aware of,” she added.
The study, “Mothers’ neural response to valenced infant interactions predicts postpartum depression and anxiety“, was authored by Megan Kate Finnegan, Stephanie Kane, Wendy Heller, and Heidemarie Laurent.