Dear Editor,

We read with great interest the recently published article by Hjorth-Johansen et al. providing important preliminary evidence regarding the use of the Norwegian version of the Paediatric Inventory for Parents among mothers of infants with CHD. ^{Reference Hjorth-Johansen, Børøsund, Tandberg and Pedersen1} Overall, the instrument demonstrated acceptable internal consistency and was able to differentiate parental stress scores according to CHD severity. However, several conceptual and methodological issues should be considered when interpreting these results.

A key issue is whether the stress measured by the Paediatric Inventory for Parents in this sample reflects CHD-specific parental stress or a broader stress response associated with early infancy. The study included mothers of infants younger than three months but did not include an age-matched comparison group of mothers of healthy infants. This limits the ability to distinguish disease-related stress from the general caregiving burden commonly experienced in the neonatal and early infancy period. For example, sleep disruption, feeding demands, hygiene care, frequent monitoring, and uncertainty are not exclusive to CHD and may also be reported by mothers of healthy infants in the same age group. Therefore, although higher Paediatric Inventory for Parents scores indicate greater reported stress, the absence of a healthy infant control group makes it difficult to determine how much of this stress is specifically attributable to CHD. Goldberg et al., who compared parenting stress among parents of infants with CHD, infants with cystic fibrosis, and healthy infants. ^{Reference Goldberg, Morris, Simmons, Fowler and Levison2} Their findings showed that diagnostic group differences were mainly observed in child-related stress, whereas groups did not differ in stress arising from life events unrelated to the target child’s illness. ^{Reference Goldberg, Morris, Simmons, Fowler and Levison2} This suggests that comparison groups are essential for distinguishing illness-related parenting stress from broader contextual or normative parental stress. Therefore, although higher Paediatric Inventory for Parents scores indicate greater reported stress, the absence of a healthy infant control group makes it difficult to determine whether these scores reflect CHD-specific distress, developmentally expected parental burden, or the cumulative effect of caregiving and psychosocial vulnerability.

The interpretation of the difficulty subscale also requires caution. Although this subscale may provide a more subjective measure of parental appraisal, it is vulnerable to reporting and perception-related influences. Parents who have been informed that their infant’s CHD is severe may perceive the same event as more threatening than parents who have received a more reassuring prognosis. This interpretation is consistent with the broader paediatric chronic illness literature. Cousino and Hazen emphasised that parenting stress is not determined solely by illness duration or clinical severity, but is also shaped by parental responsibility for treatment management and illness-related cognitive appraisals. ^{Reference Cousino and Hazen3} They further noted that perceived child vulnerability, negative perceptions of the child’s health, and reduced parental self-efficacy are associated with higher parenting stress. ^{Reference Cousino and Hazen3} Therefore, in the present context, disease severity, parental perception of prognosis, healthcare exposure, and emotional adaptation after diagnosis may be closely intertwined. The observed relationship between CHD severity and Paediatric Inventory for Parents scores should thus not be interpreted as evidence that the instrument exclusively measures CHD-specific stress. Rather, higher scores may reflect a combined effect of objective disease burden, clinical exposure, parental interpretation of risk, and the psychological meaning attributed to the infant’s diagnosis and treatment process.

Another important consideration is timing. Although CHD can represent a chronic condition from birth, mothers of infants younger than three months may not yet have experienced the cumulative burden of long-term chronic caregiving. At this early stage, parental responses may be shaped more strongly by acute post-diagnosis stress, hospitalisation, treatment uncertainty, discharge preparation, sleep deprivation, feeding problems, and postnatal emotional adjustment. Solberg et al. demonstrated that maternal psychological responses to infant CHD vary according to disease severity and change across the postpartum period. ^{Reference Solberg, Grønning Dale, Holmstrøm, Eskedal, Landolt and Vollrath4} Mothers of infants with severe CHD showed elevated symptoms at 6 and 18 months postpartum, indicating that the emotional impact of CHD may extend beyond the immediate diagnostic and hospitalisation period. ^{Reference Solberg, Grønning Dale, Holmstrøm, Eskedal, Landolt and Vollrath4} Their findings suggest that anxiety and depression may reflect distinct stages of adaptation: anxiety may be more closely linked to the initial shock of diagnosis, perceived threat to the infant’s survival, hospitalisation, and treatment uncertainty, whereas depressive symptoms may persist as parents confront ongoing concerns related to growth, feeding, respiratory or digestive problems, developmental functioning, and future quality of life. ^{Reference Solberg, Grønning Dale, Holmstrøm, Eskedal, Landolt and Vollrath4} Therefore, Paediatric Inventory for Parents scores obtained one month after discharge may reflect an early adaptation phase rather than the long-term psychosocial burden of living with a child with chronic heart disease. Longitudinal assessment would be necessary to determine whether the same stress patterns persist, increase, or decrease as families gain experience with chronic care over time.

Future research should include age-matched healthy control groups. In addition, the Paediatric Inventory for Parents should be evaluated beyond a single cross-sectional assessment, using longitudinal designs or repeated assessments at clinically meaningful time points. Such designs would help clarify whether Paediatric Inventory for Parents scores reflect transient early post-diagnosis distress, emerging chronic caregiving burden, or persistent CHD-specific parental stress.