Early cardiac surgery in infancy is associated with significant individual variability in cortisol response, with lower cortisol levels linked to greater emotional and behavioral difficulties, longer hospital stays, and lower quality parent-child relationships in preschool-aged children with congenital heart disease.
Key Findings
Results
Significant individual variability in salivary cortisol response was observed among preschool-aged children who underwent cardiac surgery in infancy.
The study used a prospective cohort design with 22 preschoolers with CHD and their parents
Child salivary cortisol was collected at three time points during a hospital-based laboratory visit
Mixed-effects models were used to examine associations between cortisol response and other outcomes
The variability in cortisol response was a primary finding highlighted across the study
Results
Lower cortisol levels were associated with greater emotional and behavioral difficulties in children with CHD.
Emotional and behavioral regulation was assessed using the parent-reported Child Behavior Checklist (CBCL)
This pattern is consistent with blunted or hyporeactive HPA axis functioning
The association suggests a link between stress physiology dysregulation and behavioral outcomes in this population
Results
Higher parent-reported traumatic stress at the time of their child's surgery was associated with lower cortisol levels in the child at preschool age.
Parent-reported traumatic stress was assessed retrospectively in relation to the child's cardiac surgery
Lower child cortisol levels were linked to higher parental traumatic stress
This finding suggests that parental stress during the infant surgical period may have lasting associations with child stress physiology
The direction of the relationship indicates a blunted rather than elevated cortisol profile in more affected children
Results
Longer hospital stays predicted blunted cortisol responses in preschool-aged children with CHD.
Hospital stay duration was examined as a predictor of cortisol response using mixed-effects models
Longer hospitalization was associated with flatter cortisol profiles, indicating HPA axis hyporesponsivity
This finding links the severity or complexity of early medical stress (as indexed by hospitalization length) to later physiological dysregulation
Blunted cortisol responses are interpreted as indicative of stress physiology disruption rather than healthy stress reactivity
Results
Children in lower quality parent-child relationships displayed flatter cortisol profiles.
Parent-child interaction quality was assessed using the Emotional Availability Scales (EAS) via observed interactions
Flatter cortisol profiles were observed in children with lower quality relational environments
This finding suggests that emotionally available relationships may buffer HPA axis dysregulation in this high-risk population
The parent-child relationship was explored as a source of co-regulation and buffering support
Discussion
Emotionally available parent-child relationships were identified as a potential buffer against HPA axis dysregulation in children with CHD.
Higher quality parent-child relationships as coded by the Emotional Availability Scales were associated with more typical cortisol profiles
The findings suggest the parent-child relationship as a co-regulatory mechanism for stress physiology
The authors identify parent-child relationship quality as a potential intervention target to support psychosocial development
Results contribute to the emerging use of stress biomarkers in CHD research
What This Means
This research suggests that babies who undergo heart surgery face significant early-life stress that can shape how their bodies and minds develop. By the time these children reached preschool age, researchers found wide differences in how their stress hormone systems (specifically cortisol, which reflects how the body responds to stress) were functioning. Notably, children with lower cortisol levels — a sign that the stress response system may be blunted or less reactive than expected — also tended to have more emotional and behavioral problems, had experienced longer hospital stays as infants, and had parents who reported higher levels of traumatic stress around the time of the surgery.
The quality of the relationship between parent and child also emerged as an important factor. Children who had warmer, more emotionally available relationships with their parents showed more typical cortisol patterns, suggesting that a supportive parent-child relationship may help protect children's stress systems from the effects of early medical trauma. This was assessed through direct observation of parent-child interactions in a hospital-based laboratory setting, alongside parent-reported questionnaires.
This research suggests that the effects of early heart surgery extend beyond physical health into children's emotional, behavioral, and physiological development. The findings point to the parent-child relationship as a meaningful target for support and intervention, and highlight the value of measuring stress hormones in children with congenital heart disease to better understand their developmental needs.
Clancy T, Weerth C, Muscara F, Jordan B. (2026). Early Childhood Emotional, Relational, and Stress-Related Outcomes Following Infant Cardiac Surgery.. Developmental psychobiology. https://doi.org/10.1002/dev.70200