Maternal Parasympathetic Regulation During Dyadic Stress: Associations with Emotional Availability, Maternal Depressive and Anxiety Symptoms, and Infant Distress
Authors: Jamieson Brittany 
Published: February 2024

<p><strong>Background:</strong> Parents, often mothers, are the primary regulators of infant emotion and physiology. Maternal self-regulation is central to the regulation of another, particularly during stress. Appropriate flexibility in the parasympathetic nervous system (indexed via respiratory sinus arrhythmia, RSA) is associated with positive self-regulation. This dissertation aimed to better understand the factors that influence a mother’s parasympathetic regulation during dyadic stress.</p>
<p><strong>Method:</strong> A community sample of 83 mother-infant dyads participated in two visits as part of a larger longitudinal study. During the first visit, at infant age 6 months, dyads were filmed as they interacted for 30-minutes at home. This interaction was later coded for maternal caregiving behaviour using the Emotional Availability Scales. Data on maternal self-reported symptoms of depression and anxiety were also collected. During the second visit, at 6.5 months, dyads participated in an experimental stressor, the still face procedure, involving three episodes: baseline interaction; a still face episode wherein a mother is instructed to remain unresponsive to the infant; and a reunion episode, wherein the mother and infant re-establish interaction. Infant distress (coded in 1 second intervals) and maternal RSA data were collected. Multilevel models assessed maternal RSA trajectories and their relation to maternal factors and infant distress in the still face and reunion episodes.</p>
<p><strong>Results:</strong> In the still face episode, maternal depressive symptoms, anxiety symptoms and infant distress interacted to predict maternal RSA. Mothers with fewer symptoms of depression and anxiety showed appropriate RSA withdrawal in the context of infant distress, consistent with an adaptive physiological response. In comparison, mothers with more depressive symptoms and high or low anxiety symptoms had increasing RSA trajectories in this context, suggesting less adequate physiological mobilization. Mothers with fewer depressive symptoms and high anxiety symptoms displayed the steepest RSA withdrawal in this episode, suggesting parasympathetic hyperarousal. In the reunion episode, maternal depressive symptoms and emotional availability interacted to predict maternal RSA trajectories. Mothers with fewer depressive symptoms and greater emotional availability displayed trajectories that were consistent with physiological mobilization at the start of the reunion and recovery towards the end. In comparison, mothers with greater depressive symptoms and less emotional availability displayed limited physiological mobilization at the start of the reunion and less physiological recovery towards the end.</p>
<p><strong>Conclusions:</strong> Findings illustrate the importance of assessing: (i) physiological regulation dynamically, (ii) maternal mood, anxiety, and caregiving in interaction, and (iii) self-regulation in the context of co-regulation. Further, these results highlight differential parental task demands between the still face episode and the reunion episode. Public health implications and future research are discussed.</p>