CHD is the most prevalent congenital defect diagnosed in 1:100 live births.Reference Marino, Lipkin and Newburger1 Complex CHD conditions that require surgical interventions early in life and prolonged hospitalisations can be life-threatening (e.g., Hypoplastic Left Heart Syndrome) and cause profound stress to families who face health and quality-of-life issues.Reference Marino, Lipkin and Newburger1,Reference Lisanti, Golfenshtein and Medoff-Cooper2 The first year after the baby is born (i.e., infancy; 0–12 months of age) is critical, as during this year most surgical interventions occur. The initial period of hospitalisation and early care of an infant with complex CHD at home requires parental adjustment to the environment of cardiac ICU and to the multiple post-surgical caretaking demands.Reference Sarajuuri, Lönnqvist, Schmitt, Almqvist and Jokinen3 Parents who are required to adhere to the continuous and complicated post-operative medical needs, often experience excessive burden and may feel incompetent in providing the needed care for their child. Among the issues parents face are included, for example, feeding and growth failure problems, haemodynamic and respiratory instability, risk for infections, and developmental delays. The parenting stress levels in the paediatric CHD population are higher compared to other (healthy or sick) paediatric populations, and often resulting from the care burden and parental feelings of incompetence.Reference Sarajuuri, Lönnqvist, Schmitt, Almqvist and Jokinen3-Reference Uzark and Jones5 High parenting stress levels have been widely linked to adverse outcomes in individuals and families, such as parental anxiety and depression, disturbed parent–child relationship,Reference Fonseca, Nazaré and Canavarro6,Reference Goldbeck and Melches7 decreased familial wellbeing and quality of life,Reference Bishop, Gise, Donati, Shneider, Aylward and Cohen8,Reference Pinquart9 maladaptive behaviours, and poor social competence among children.Reference Pinquart9,Reference Hearps, McCarthy and Muscara10
Richard Abidin has conceptualised the various stress-evoking factors with regard to the parenting role and the parent-child system, and categorised them in his Parenting Stress ModelReference Abidin11 into Parent and Child domains. The factors within the Child Domain include behavioral and temperamental characteristics of the child, and the perceptions and expectations of parents towards their child. Such factors include, for example, child’s demandingness, mood, distractibility, parental acceptance of their child’s characteristics, and parental feelings of reinforcement. The factors within the Parent Domain include parental personality and functional components (competence, attachment), spousal support, parental physical and mental health, social isolation, and role restriction. General life-situational circumstances are perceived as moderators of parenting stress in this model. Most of the stress sources reported by research align with Abidin’s model. However, certain condition-unique characteristics arise within the child or the parenting role demands, such as the children’s irritable temperaments.Reference Uzark and Jones5,Reference Dudek-Shriber12-Reference Marino and Lipshitz14 Stressors reported in this population also include poor parental competence related to the medical fragility of the child at the critical care unit, and to the caretaking burden at home after discharge.Reference Sarajuuri, Lönnqvist, Schmitt, Almqvist and Jokinen3,Reference Torowicz, Irving, Hanlon, Sumpter and Medoff-Cooper13,Reference Farley, DeMaso and D’Angelo15,Reference Lisanti, Allen, Kelly and Medoff-Cooper16
Although parenting stress has gained research attention in recent years in the CHD paediatric populations, longitudinal stress trajectories over infancy have not been studied yet. The infancy period (0–12 months of age) is critical for establishing a healthy infant–parent relationship.Reference Bowlby17 This is important for the family system readjustment to the new structure, roles, and routines and may directly impact infant development.Reference Sprunger, Boyce and Gaines18 Whereas the general expectation from parenting stress is to diminish over time as part of the normal adjustment process to the parenting role,Reference Abidin11 critical paediatric cardiac condition introduces additional complexities to the process, which may alter the natural trajectory of the familial readjustment.Reference McCubbin and Patterson19 The aim of the current study was to examine changes in parenting stress over infancy in mothers of infants with CHD and compare them to those of mothers of healthy infants.
Materials and methods
The current study obtained data from a larger prospective cohort study. The parent study was conducted at the Children’s Hospital of Philadelphia. Two hundred and one mother–infant dyads were recruited at initial hospital discharge and followed during four additional time points over their infancy – at three, six, nine, and twelve months of age, during their paediatric follow-up visits. Mothers of infants with complex CHD were recruited via convenience sampling from the hospitals’ cardiac ICU; mothers of healthy infants were recruited via convenience sampling from regional primary care practices. Inclusion criteria for infants in the CHD group included 1) Diagnosis of a complex cardiac condition requiring a corrective or palliative surgery within the first six weeks of life, 2) birth at or above 35 gestational weeks, 3) birthweight of 2000 grams and above. Exclusion criteria included non-cardiac congenital anomalies or genetic syndromes other than DiGeorge syndrome and 22q deletion. Healthy infants included in the study were born above 35 gestational weeks, with no congenital anomalies, genetic syndromes, or health conditions after birth. Infants in both groups were age matched at the 3–12 follow-up visits. The sample size for the current study was 129 mothers, who had parenting stress data, and their infants.
The study gained institutional review board approval and mothers provided informed consent. The research team obtained data during five time points – at hospital discharge, and further at three, six, nine, and at twelve months of age during outpatient visits. Mothers completed self-report questionnaires of parenting stress, infant temperament, and demographic information. Clinical information was obtained from infants’ medical records (For further information with regard to the parent study please see.Reference Medoff-Cooper, Irving and Hanlon20
Mothers completed the Parenting Stress Index-Long Form (PSI-LF) at three-, six-, nine-, and twelve-month follow-up physician visits. The PSI-LF consists of 120 self-report, 5-point Likert scale items, with subscales measuring stressors within the Child and Parent Domains as conceptualised in Abidin’s Parenting Stress Model.Reference Abidin11 Forty-seven items measure the six Child Domain stressors (Distractibility, Adaptability, Reinforcement, Demandingness, Mood, and Acceptability). Item for example to assess the Demandingness factor: “My child seems to be much harder to care for than most”. Item to assess the mood factor: “My child seems to cry or fuss more often than most children”. Item to assess the Acceptability factor: “My child looks a little different than I expected, and it bothers me at times”. Fifty-four items measure the seven stressors within the Parent Domain (Competence, Isolation, Attachment, Health, Role restriction, Depression, Spouse support). Item for example to assess parental Competence: “When my child came home from the hospital, I had doubtful feelings about my ability to handle being a parent”. Item to assess the attachment factor: “I expected to have closer and warmer feelings for my child than I do, and this bothers me”. Item to assess parental role restriction: “I feel trapped by my responsibilities as a parent”. Domains’ scores are summed to a Total Stress score, with higher score indicating higher parenting stress. The PSI demonstrates good validity and reliability psychometrics, and has been in use in the CHD population.Reference Bishop, Gise, Donati, Shneider, Aylward and Cohen8,Reference Medoff Cooper, Marino and Fleck21,Reference Kaugars, Shields and Brosig22 Covariates considered for analysis included Clinical and Demographic characteristics. Clinical parameters were obtained from infants’ medical records and included post-operative heart physiology (single- versus bi-ventricular physiology for the CHD group),Reference Medoff Cooper, Marino and Fleck21 and infant WHO growth z-scoresReference Medoff-Cooper, Irving and Hanlon20 for both groups. Demographic characteristics were self-reported by mothers and included infant gender, maternal education, race, and ethnicity.
Analyses were performed in STATA 16 statistical package.Reference Kaugars, Shields and Brosig22 Descriptives included central tendency and variation measures (mean, median, standard deviation, and ranges). A linear mixed-effects model analysis was performed to examine changes in parenting stress over time.Reference Khairy, Poirier and Mercier23 The estimates produced are robust to missing data and dropout.24 We examined patterns of missing data for bias and compared estimates from a complete data analysis to estimates generated from an imputed data set. No systematic bias in missingness patterns was evident.Reference Longford25 Parenting stress outcomes (Child Domain, Parent Domain, and Total Stress) were separately regressed over the independent variable of time (continuous parameter represented by infants 3–12 month’s follow-up visits). Covariates included in the analysis were identified in main effect bivariate models, and in two-way interaction (Covariate x Visit) bivariate models (α = 0.2), and were further eliminated via the backwards deletion process. The covariates included in the final multivariable models were mothers’ education, race, and infant length z-scores. Parenting stress changes over time group comparisons relied on Group x Visit interaction term estimates (α = 0.05).
Results
Sample’s demographic characteristics, baseline growth, and group stress comparisons are presented in Table 1. The 129 infants included in the final sample were predominantly non-Hispanic (n = 110; 86%), white (n = 105; 82%) males (n = 84; 66%). The CHD group constructed 58% of the sample, and almost half of this group (48%) had single-ventricle functioning heart (see defects distribution in Table 2). The median length of stay at the initial hospitalisation for infants in this group was 15 (2-159) days. Groups significantly differ by mothers’ race and education level. Healthy infants had significantly higher growth parameters at baseline (3 months). Child Domain parenting stress was significantly higher for mother in the CHD group at baseline (p = 0.040). Table 3 presents the PSI scores for the two groups and the PSI measure’s percentile ranking as were derived from age appropriate frequency distribution of a normative samples.Reference Abidin11 Finding indicate stress levels ranging from the 30–45th percentiles in the CHD group, and 25–35th percentiles in the Healthy group, across the various follow-up visits.
aGroup comparisons via t-tests for continues parameters, and Fisher’s Exact test for categorical parameters; bstandard deviation; cinterquartile range; dWHO growth z-score at 3 months
aStandatd deviation; bPSI percentile ranking derived from the age appropriate frequency distribution of normative samples (Abidin, 1995)
Tables 4 and 5 display results from Mixed Effects regression models. In these sets of multivariable models. PSI subscales were separately regressed over the independent variable of time (represented by infant visits at three, six, nine, and twelve months). Models were adjusted for infant length z-scores, mothers’ education, and ethnicity. Table 4 presents the main effects of Visit (the groups’ individual stress change over time) for the various PSI outcomes. Findings demonstrate a general stress decrease in mothers of CHD infants and a general stress increase in mothers of healthy infants over time. Specifically, stress in the CHD group has significantly decreased over time on the Parent Domain (p = 0.025), whereas stress in the healthy group has significantly increased over time on the Child Domain (p = 0.033). No significant changes over time in the Total Stress scores were found in either group. Table 5 further presents group differences in PSI trajectories as represented by the Visit x Group interaction term. Parenting stress trajectories significantly differed between groups on the Parent Domain (p = 0.026) and on the Total Stress (p = 0.039) subscales. No significant differences were demonstrated on the Child Domain. Group comparisons for the Total Stress trajectories are graphically presented in Figure 1.
aAll models are adjusted for mothers’ education, race, and infant length z-scores; b estimates in table correspond to main effect of “Visit”; Visit represents the independent variable of time (continuous); c Parenting Stress Index subscales scores as the outcome of interest, each represents a separate multivariable model within each group, CHD and healthy; dstandard error; e95% confidence intervals
aModels are adjusted for mothers’ education, race, and infant length z-scores; b Visit represents the independent variable of time (continuous); cCHD versus healthy infants; dParenting Stress Index subscales scores as the outcome of interest, each represents a separate multivariable
Discussion
Our study aimed to examine changes in parenting stress of mothers of infants with complex cardiac defects and compare them to those of healthy infants over infancy. Findings indicate higher initial child-locused stress levels in mothers of cardiac infants, compared to mothers of healthy infants. Findings also indicate a general decrease in stress over time in mothers of infants with CHD and a general increase in stress in mothers of healthy infants. The decreases in parenting stress in the CHD group appeared to be primarily in parent-locused stress, whereas the increases in parenting stress over time among mothers of healthy infants were primarily in the child-locused domain. The stress trajectories significantly differ between groups on both Parent Domain and Total Stress subscales. Surprisingly, the stress levels of our sample seem to be ranked mildly lower when compared to normative sample distributions. This trend of lower-than-expected scores across both groups is surprising, as healthy controls’ mean should correspond to the 50th. According to Abidin,Reference Abidin11 this might result from several factors, such as defensive, or socially desirable responding to the questionnaire, or due to parental disengagement in the parental role. It is also possible that the sample we recruited was relatively homogenous in terms of higher SES levels, and therefore had lower stress levels. Findings suggest that the higher early stress, at three months of age, experienced by mothers of cardiac infants is related to child characteristics. Indeed, infants with CHD possess distinct characteristics and challenges unique to the early infancy period including difficult temperaments, irritability, and feeding issues, these are added to the general illness condition and in-hospital medical fragility and the cardiac ICU stay.Reference Torowicz, Irving, Hanlon, Sumpter and Medoff-Cooper13,Reference Marino and Lipshitz14,Reference Hedeker and Gibbons26 The post-operational period and the lengthy cardiac ICU stay have been described as peak stressful periods for parents.Reference Rubin27 The post-discharge period is critical as well, especially for infants with single-ventricle, who remain within the interstage mortality zone until the second surgery at four to six months of age.Reference Osborne and Reed28 The second surgery is probably an additional stressful period for these parents; however, this was not reflected in our findings, perhaps due to the spacing of the follow-up measurement that potentially could have missed the peak stressful period and reflect the stress when it has already decreased. With time, most infants become more medically stable and require fewer treatments and physician visits and parents learn how to manage medications and the condition.Reference Lisanti, Golfenshtein and Medoff-Cooper2,Reference Wei, Roscigno, Swanson, Black, Hudson-Barr and Hanson29
Our findings indicated significant decrease in parent-locused stress over time. The stress on the Parent Domain may reflect, among others, the parental mental health associated with their infant condition. Studies have found that mothers experience mental health symptoms during their infants’ hospitalisation, such as anxiety, depression, and post-traumatic stressReference Lisanti, Allen, Kelly and Medoff-Cooper16,Reference Trivedi, Smith, Barker, Jaggers, Lodge and Kanter30,Reference Franck, McQuillan, Wray, Grocott and Goldman31 and that their mental health may be impacted long after hospital discharge.Reference Gaskin, Cooper, Rooney, Mohammed and Barron32 These symptoms may have further implications on mothers’ familial functioning and relationships with their infants.Reference Woolf-King, Anger, Arnold, Weiss and Teitel33 Many studies have described mothers’ feelings of incompetence in their maternal role when caring for their infant in this population. However, studies have also shown that parents grow into the parenting role as a result of their adjustment to the CHD condition and to the care burden over time.Reference Berant, Mikulincer and Shaver34,Reference Pinelli, Saigal and Bill Wu35 Gaskin et al.Reference Trivedi, Smith, Barker, Jaggers, Lodge and Kanter30 showed a decrease in post-traumatic stress symptoms in parents of infants who underwent cardiac surgery, as their parental confidence increased.
As our findings suggest, mothers’ experiences and needs may change over time, and maternal mental resilience, as well as certain individual-familial factors, may play a role in their successful adjustment to the condition.Reference Fedele, Mullins, Wolfe-Christensen and Carpentier36,Reference Tsai, Hsu and Chou37 Intervention in this population should be implemented early, perhaps even targeted during the hospitalisation to support maternal mental health and reduce initial stress and anxiety.Reference Rychik, Donaghue and Levy38,Reference Sira, Desai, Sullivan and Hannon39 Furthermore, interventions should be designed to empower mothers, while promoting constructive parenting practices and maternal adaptive coping strategies within the broader context of family and community. Research indicates that interventions aimed at changing parental illness perceptions and coping mechanisms were most effective in reducing parenting stress.Reference Hancock, Pituch and Uzark40,Reference Kasparian, Kan, Sood, Wray, Pincus and Newburger41
In mothers of healthy infants, infant-locused stress appeared to increase over time. AbidinReference Abidin11 mentioned that parenting stress should be expected to decrease between 1 and 3 years of age in the general population. Both DysonReference Golfenshtein, Srulovici and Deatrick42 and Crnic et al.Reference Jackson, Frydenberg, Liang, Higgins and Murphy43 found stable parenting stress levels in healthy preschool children over time. Nevertheless, we could not find any earlier evidence for parenting stress trajectories during infancy. The stress increase in the healthy group in our study may perhaps be explained by infants’ temperamental and behavioural repertoire development over time.Reference Dyson44 Also the increase in stress may be attributed to the mothers’ return to work after several months postpartum.Reference Crnic, Gaze and Hoffman45,Reference Calkins, Dedmon, Gill, Lomax and Johnson46
Our study has several limitations arising from non-excluding infants with certain genetic syndromes (DiGeorge and 22q deletion), which were unapparent at the time of recruitment and may have biased results. Additional limitations arise from the secondary nature of analysis restricting sample size and availability of other family variables. The sample only included mothers. Studies examining fathers and mothers have demonstrated different patterns of parenting between parents.Reference Sarajuuri, Lönnqvist, Schmitt, Almqvist and Jokinen3,Reference Dudek-Shriber12 It was hard to understand/interpret maternal education with the high rate of missing. Maternal education, SES, and other family variables may play a role in shaping the parenting stress trajectory and should be accounted for in future studies. Moreover, although validated in the paediatric cardiac population, illness-related factors are currently absent from the PSI,Reference Nichols and Roux47 preventing from identification of illness-specific stressors. It would be of interest to examine further moderators of stress change in parents of these infants. Although we accounted for dropout and missingness in our analysis with no evidence of bias,24 this certainly limited the power of our study. A post hoc power analyses indicated that we had only 50% power to detect significant effect for the Child Domain (as compared to 76% power for the Parent Domain and Total Stress). This potentially prevented us from identifying a significant effect, if existed, within this domain. Furthermore, using a continuous measure of “time” provided linear results for the stress trajectories. Non-linear analysis may provide more detailed information of potential peak stressful periods in infancy. Previous research has identified the early post-surgical period as very stressful for mothers of cardiac infants.Reference Wei, Roscigno, Swanson, Black, Hudson-Barr and Hanson29,Reference Fedele, Mullins, Wolfe-Christensen and Carpentier36 This population might benefit from close screening of stress through and beyond infancy. Due to the lower-than-expected stress levels in our sample, we suspect that our findings may present a response bias (social desirability, or willingness to complete the screener due to lower stress). Future studies should recruit more heterogeneous populations, from various SES levels, and demographic backgrounds.
Acknowledgements
None.
Financial support
This work was supported by the National Institutes of Health R01NR002093.
Conflicts of interest
None.
Ethical standards
The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national guidelines on human experimentation (USA) and with the Helsinki Declaration of 1975, as revised in 2008, and has been approved by the institutional committees (Children’s Hospital of Philadelphia).