Conflict is a typical aspect of all relationships. However, conflict that is characterized by high intensity and frequency can significantly impact the couple relationship and individual wellbeing (Birditt et al., 2010; El-Sheikh et al., 2013). This is of particular importance for co-parenting relationships, where interparental conflict (IPC) can influence offspring outcomes (O’Hara et al., 2023). Though conflict is often challenging to define, this paper conceptualizes it as situations that “occur frequently, are expressed with hostility, and are poorly resolved” (Harold et al., 2016). This definition sharply distinguishes conflict from domestic abuse, which manifests an imbalance in power (Department for Work & Pensions, 2017).

The Impact of Interparental Conflict on Family Outcomes

Conflict within co-parenting couples naturally oscillates over the course of relationships and is a consistent contributing factor to a range of family outcomes (Totenhagen et al., 2016). Constructive conflict behaviour exhibited by parents, often marked by positive communication strategies, problem-solving, negotiation, and cooperation, are generally associated with enhanced family outcomes, particularly regarding child development (McCoy et al., 2009). Contrastingly, the impact of destructive conflict resolution behaviour appears to be detrimental. Destructive conflict behaviours (such as anger, defensiveness, accusations, and withdrawal) are associated with an elevated risk of parental mental health symptoms, couple separation, and child internalising/externalising disorders (Birditt et al., 2010; El-Sheikh et al., 2013; Warmuth et al., 2020).

The significant implications of IPC for families have prompted the development of several theories examining the pathway between IPC and these outcomes. For example, the Emotional Security Theory (Cummings & Davies, 1996) posits that the relationship between IPC and child maladjustment is underpinned by unresolved fear following exposure to heightened conflict. However, the most prominent theoretical perspective is the Spillover Hypothesis (Easterbrooks & Emde, 1988) which suggests that frequent IPC can elevate parental stress over time (van Dijk et al., 2020). These challenges can ‘spill over’ into parenting behaviour, diminishing parents’ ability to respond suitably to their child’s cues, thereby undermining the quality of parenting (Zhou et al., 2017). This theory is substantiated by research correlating higher levels of IPC with an increased adoption of negative parenting practices linked with adverse child outcomes (van Dijk et al., 2020).

Parenting Interventions Targeting Interparental Conflict

The aforementioned theories have underpinned the development of interventions aiming to enhance conflict resolution strategies among couples. The foremost objective of interventions targeting IPC is to foster positive parenting practices and enhance the co-parenting relationship through couple, family, and group therapies (Harold et al., 2016). The significance of these interventions is unambiguous, and they have readily been integrated into healthcare services across Western societies. For instance, in the USA, couples undergoing court divorce proceedings are frequently required to participate in IPC-targeting interventions (Fackrell et al., 2011). In England, various parenting interventions have been made available through NHS services following the governmental Reducing Parental Conflict (RPC) program (Department for Work & Pensions, 2021). The adoption of such interventions is widely endorsed, as emphasised by Harold et al’s (2016) review. Harold and colleagues concluded that parenting interventions targeting IPC are successful in enhancing IPC behaviour, parental communication, relationship satisfaction, and positive child outcomes. Similarly, Harold and Sellers’ (2018) review associated interventions targeting IPC with improvements in couple relationship quality, communication, coparenting, and parental depressive symptoms. However, considering that the most recent review was completed 7 years ago, it is conceivable that more recent evidence regarding the effectiveness of interventions targeting IPC has since become available.

The Evidence Gap

While conflict typically fluctuates throughout family life, escalations are often noticed during the transition to parenthood (Huss & Pollmann-Schult, 2020). Pregnancy and the perinatal period can heighten stress levels and challenges in adjusting to new roles within the couple relationship (Delicate et al., 2018). These stressors can amplify relationship distress and IPC levels, increasing families’ susceptibility to IPC and its associated negative outcomes. This period is therefore presented as an opportune time where interventions could prove particularly effective in mitigating the long-term consequences of destructive IPC. However, a significant portion of the research investigating IPC interventions concentrates on families with older children, up to 18 years old. This limitation also applies to Harold et al.‘s (2016) review which omitted evidence concerning children aged under 5 years, creating a noticeable gap in the evidence concerning the impact of early intervention.

Objectives of the Present Review

We sought to bridge this gap in the literature by offering an updated summary of evidence that evaluates the efficacy of interventions targeting IPC in enhancing family outcomes. Additionally, we aimed to underscore intervention outcomes in families with children aged between 0 and 5 years. This information will guide the development and evaluation of future interventions and will aid in making recommendations for health service provision. The research questions explored are as follows:

1. Are interventions that target IPC clinically effective in improving family outcomes?
2. Are interventions that target IPC clinically effective in improving family outcomes when administered during the first five years of a child’s life?

The primary outcome of interest is any possible change in reported IPC behaviour post-intervention (e.g., alterations in frequency, intensity, and type of behaviour). Secondary outcomes to be explored are any changes in parenting behaviour and child development (including but not limited to, physical, cognitive, and psychological development) post-intervention.

Methods

Inclusion Criteria

Inclusion criteria were determined prior to the search by the research team (comprising two Co-Chief Investigators and one Research Assistant). Eligible articles reported on a manualised/defined intervention (i.e., the intervention must have structured procedures/content, and a clearly described theoretical model) incorporating a component that targeted the co-parental relationship, delivered to co-parents with offspring aged 0–11 years. All articles employed a comparison between intervention and control groups of participants and report pre-and post-intervention evaluations of IPC, parenting behaviour, and child development outcomes. The requirement of pre- and post-intervention measurements was included in the criteria to allow exploration of causal inferences of the intervention outcomes and the theoretical pathways linking IPC to parenting behaviour and child outcomes. Conformity of articles to the inclusion criteria (complete search criteria are provided in Appendix 1) was verified by two members of the research team.

Search Strategy

The literature search, conducted in October 2024, followed the guidelines from the Cochrane Handbook for Systematic Reviews of Interventions (Higgins & Green, 2011). A systematic process was selected for this review over alternatives, such as scoping reviews, as this methodology supports the investigation of specific research questions (Munn et al., 2018). The research team developed and refined search terms (outlined in Appendix 2) across three domains: co-parenting, conflict within the partnership, and supportive interventions. The search terms explored four databases (MEDLINE, PsychInfo, PsychExtra, Social Policy and Practice), and the research team also manually examined reference lists, and reviewed multiple scoping reviews concluded prior to this systematic review.

Study Selection and Data Extraction

After removing duplicate entries, the relevance of all citations resulting from the search was assessed by the study team. Articles that potentially met the eligibility criteria underwent a full-text review. Any queries regarding publication adherence to the inclusion criteria were discussed among the team until a consensus was reached. After this process, a final set of 23 articles was identified for inclusion (a detailed overview of the entire study selection process is provided in Appendix 3). The final articles underwent a quality review by the study team, using the Cochrane Risk-of-Bias Tool for Randomised Trials (Higgins et al., 2011) and the ROBINS-I Tool (Sterne et al., 2016).

Results

Study Characteristics

The 23 articles reported on 25 different parenting interventions targeting IPC, all of which were categorised as either psychoeducational or skills-training based programmes. Nine of these interventions were variations of Triple P, a parenting program designed to enhance positive parenting behaviour and support child behavioural difficulties (de Graaf et al., 2008). The samples’ parental age ranged from 18 to 76 years (M = 35.32, SD = 3.82), while the child age ranged from 22.8 weeks gestation to 10.6 years. The sample size varied from 21 to 1041 families, primarily drawn from Western countries (n = 21 studies). The sample populations included targeted populations from low-income areas and/or families expressing concerns related to child behaviour, co-parenting difficulties, IPC, parental separation, or clinical mental health issues.

Interventions Focusing on Intact Couples

Eight interventions analysed in the review explicitly targeted intact couples (see Table 1). All interventions were developed in Western countries, spanning the USA (n = 4), Australia (n = 1), Ireland (n = 1), and Switzerland (n = 1). These interventions (Group Triple P, Family Foundations, Couple Coping Enhancement Training, Parenting-Focused Group, Marital-Focused Group, Parent-Only Group, Parent-Child Group, Parents Plus-Parenting While Separated) were delivered in a group format to couples who were maintaining a romantic relationship. Couples were advised to attend intervention sessions jointly, except for the Group Triple P programme, which required individual attendance. The primary focus of these interventions was enhancing a positive couple relationship by fostering conflict resolution strategies, couple coping, communication skills, and awareness about the impact of IPC on children.

The reported effects of these interventions on IPC, parenting, and child outcomes are detailed in Table 2. The Family Foundations, Parenting-Focused Group, and Marital-Focused Group interventions all demonstrated significant improvements in IPC behaviour. Since no difference was found between the Parent-Only and Parent-Child Groups, Cummings et al. (2008) treated them as one intervention and found significant improvements in IPC compared to the control group. The Group Triple P programme reported a significant improvement in the “burden” subscale of the Parent Problem Checklist following the completion of the intervention, but this was not echoed in father-reported IPC, and no significant changes were found in any other subscales. Similar results were reported for parenting behaviour following the Group Triple P intervention. The programme led to significant improvements in mothers’ sense of parental competence, over-reactivity, and overall parenting, but these findings were not echoed in the fathers’ reports. Group Triple P was the sole intervention related to significant enhancements in parenting behaviour, but it did not impact child outcomes. Conversely, the Family Foundations intervention proved particularly effective in improving infant soothability and attention, whilst the Parenting-Focused Group and Marital-Focused Groups showed improvements in child hyperactivity. The combined results of the Parent-Only and Parent-Child Groups identify associations between improvements in IPC behaviour and mother reports of parenting behaviour and child adjustment. The Couple Coping Enhancement Training intervention did not demonstrate significant improvements in IPC, parenting behaviour, or child outcomes.

Interventions Targeting Separated Couples

Seven interventions outlined in Table 1 were designed to enhance IPC in parents who were separated or currently undergoing divorce. These interventions were administered in a group setting, with each parent encouraged to attend alone. The interventions aimed to improve parenting and relationship behaviours to enhance parental relations and overall family well-being, focusing on communication strategies, conflict resolution management, and disciplinary behaviours. Most interventions were developed in the USA (n = 4), with one each in Australia (Triple P Positive Parenting Programme) and Ireland (Parents Plus-Parenting When Separated). Evaluations of these interventions followed a randomised-controlled trial (RCT) design, although Cox et al.‘s (2021) assessment of the Co-parenting for Resilience intervention had to utilise a non-randomised design with matched controls, as participants were court-mandated to complete the intervention.

The efficacy of interventions targeting separated couples in improving family outcomes is summarised in Table 3. The Co-parenting for Resilience and Parents Plus-Parenting While Separated programmes were associated with significant improvements in IPC. All other interventions in this group were ineffective in reducing the frequency or intensity of IPC. Overall, interventions aimed at separated couples were successful in improving parenting behaviours, particularly, over-reactivity, verbosity, warmth, rejection, and effective discipline. However, these outcomes were mostly inconsistent across various measures and time points, especially the New Beginnings Program and New Beginnings Program-Dads. The Mother Program and Mother and Child Dual Program showed the most consistent improvements in disciplinary behaviour across multiple time points. Similarly, all interventions were successful in improving some aspect of child development, despite inconsistencies across all outcome measures and evaluation points. Interventions appeared particularly effective in supporting child behaviour difficulties, social competence, and coping behaviours.

Interventions Targeting both Intact and Separated Couples

Fourteen parenting interventions aimed at enhancing IPC among parents irrespective of their relationship status were evaluated (see Table 1). Most of these were developed in Australia (n = 9), with the remainder developed in the USA or Canada (n = 5). The Self-Directed-, Enhanced Self-Directed-, Online- and Online Brief-Triple P interventions are designed to be completed by parents individually at their convenience. Enhanced Triple P and Standard Triple P were delivered to couples by trained facilitators, whereas all other interventions were group sessions delivered to individual parents. The principal aim of the intervention content was to support effective child behaviour management and promote a positive co-parenting relationship. All evaluations of these interventions employed RCTs primarily in Western countries, with two studies executed in Vietnam and Hong Kong.

As detailed in Table 4, the TRUE Dads, Supporting Father Involvement, and Group Triple P + BCA interventions were associated with marked improvements in IPC. Although Leung et al. (2003) associated short-term improvements in IPC with Group Triple P, significant enhancements in the “problem” subscale of the Parent Problem Checklist at a 3-month follow-up were only reported by Matsumoto et al. (2007). The Triple P Online intervention produced mixed results, with significant improvements observable at a 6-month follow-up, but not at earlier assessments. All other interventions that targeted both intact and separated couples exhibited no significant changes in IPC.

Significant advancements in parenting behaviour were linked to the Dealing with Disobedience Discussion Group, Supporting Father Involvement, Enhanced Self-Directed Triple P, Group Triple P + BCA, Triple P Online, and Triple P Online Brief interventions. However, parenting outcomes for the remaining programmes were mixed. Group Triple P demonstrated substantial gains in parenting behaviour in Leung et al. (2003), but Matsumoto et al. (2007) reported a significant shift in the verbosity subscale of the Parenting Scale only. Sanders et al. (2000) identified significant enhancements in parenting behaviour following the Enhanced Group Triple P, but Hoath and Sanders (2002) did not replicate this. Both Self-Directed and Standard Triple P showed substantial improvements in mother’s sense of parental competency, but such improvements were not evident in father reports.

Group Triple P + BCA, Group Triple P, Triple P Online, Enhanced Self-Directed Triple P, Standard Triple P, and the Dealing with Disobedience Discussion Group were all associated with significantly improved child outcomes. The remaining interventions yielded mixed results. The Triple P Online Brief notably improved parental reports of child behavioural difficulties in the “intensity” subscale of the Eyberg Child Behavior Inventory (ECBI). This subscale of the ECBI reflects how often children exhibit behaviours such as “temper tantrums” (Eyberg & Pincus, 1999). The Enhanced Triple P, as per Sanders et al.’s (2000) study, showed significant improvements in child behavioural difficulties, but this was inconsistent with Hoath and Sanders (2002) finding. Cowan et al. (2019) linked the Supporting Father Involvement programme with significant enhancements in adaptive child behaviour, but this was not found in Cowan et al.’s (2009) study. Regarding Self-Directed Triple P, Sanders et al. (2000) recorded substantial improvements only in mother-reports of child behaviour whereas Markie-Dadds and Sanders (2006) reported changes only in the “problem” subscale of the Parenting Scale.

Interventions in the First Five Years

A subgroup of thirteen articles in the review focused on samples with an average child age of 0–5 years (refer to Table 5). Out of these, three interventions were directed towards IPC in intact couples, while the remaining ten studies considered interventions delivered to co-parents of any relationship status. Study results within this subgroup suggest that the age of the child does not significantly impact overall intervention outcomes. Certain interventions, including Family Foundations, Parenting-Focused Group, Marital-Focused Group, Group Triple P, and TRUE Dads, were linked with significant improvements in IPC within this population. In relation to parenting behaviour, substantial advancements were observed following the Dealing with Disobedience Discussion Group, and Group-, Online-, Online Brief-, Enhanced-, and Standard Triple P interventions. Furthermore, several interventions were associated with significant improvements in child outcomes. These include the Group Triple P, TRUE Dads, Family Foundations, Dealing with Disobedience Discussion Group, Triple P Online, and Standard Triple P interventions.

Discussion

In the face of negative outcomes strongly correlated with destructive IPC, the efficacy of parenting interventions explicitly targeting IPC remains hazy. This systematic review endeavours to expand the present discussion surrounding parenting interventions centred on IPC, exploring existing evidence and pinpointing potential avenues for future intervention development and assessment. Throughout this review, 25 parenting interventions were analysed. However, the broad variation in intervention content, outcome metrics, and research methodologies employed across these studies posed considerable challenges in drawing unambiguous conclusions regarding the interventions examined. Despite this, a number of pivotal findings emerged, as discussed below.

Intervention Effectiveness: Interparental Conflict

A prominent finding is that parenting interventions typically yield more effective IPC reductions when executed in a group format as opposed to individualised parental delivery. Broadly speaking, interventions targeting intact couples appeared to demonstrate greater efficacy in enhancing IPC as compared to those designed for separated parents. Nevertheless, endorsement was also expressed for the Triple P Online, TRUE Dads, Supporting Father Involvement, and Group Triple P programmes when these were administered to co-parents, irrespective of their relationship status. These findings are key to inform future development of parenting interventions targeting IPC, and the choice of interventions prescribed by governmental health care services and court proceedings.

Notably, this review illuminated substantial difficulties associated with IPC measurement. The Parent Problem Checklist was the favoured instrument for assessing IPC behaviour, in spite of prior conclusions suggesting an inadequate evidential basis to validate its use for this purpose (Pote et al., 2020). This exacerbates the complexity in drawing conclusions concerning the effectiveness of interventions in enhancing IPC, thereby underscoring a pressing need for the conception and evaluation of alternative IPC assessment tools to better facilitate the appraisal of interventions.

Intervention Effectiveness: Parenting Behaviour

With respect to parenting behaviour, interventions designed for separated couples have been shown to notably improve parenting practices. The aspects of parenting behaviour under scrutiny included parental warmth, discipline strategies, co-parental communication, and over-reactivity. Interventions found to effectively bolster these behavioural constructs invariably incorporated a component focused on specific parenting behaviours. However, the applicability of the evidence here is restricted by its geographic scope. This research has been undertaken in predominantly Western countries. This bias poses a challenge, given that stigma surrounding divorce in some Asian communities reportedly encourages couples to remain in high-conflict marriages where child exposure to IPC may be greater (Morrison & Coiro, 1999). Furthermore, prior research suggests that the results of parenting interventions may vary across cultures due to differences in economic constraints and parental roles (Kumpfer et al., 2002). Comprehensive assessment of interventions in non-Western countries, but also across different ethnic groups in the same country, will provide essential insight into intervention effectiveness. For instance, comparing the acceptability and effectiveness of IPC interventions between different ethnic groups within the UK would offer insights into cultural variations and help tailor strategies to community needs. However, it should be noted that several studies adapted materials to meet cultural diversity. Matsumoto et al. (2007), Hoang et al. (2022), and Leung et al. (2003) each translated intervention materials and/or outcome measures to languages commonly used by target populations (Japanese, Vietnamese, and Chinese respectively). Hoang et al. (2022) also considered the impact of the intervention (Group Triple P + BCA) on grandparenting behaviour in Vietnam. This research reflects the varying role that grandparents play in childcare across different cultures. Future research should look to expand the understanding of parenting interventions targeting IPC across different cultures and how these can be safely adapted.

It is also important to highlight that several studies included in the review reported inconsistencies in intervention effectiveness between parents. Improvements in parental competence, and parenting behaviour following Group, Self-Directed, and Standard Triple P were reported by mothers only (Bodenmann et al., 2008; Sanders et al., 2000). These findings reflect wider literature indicating that Triple P interventions are disproportionately more effective in supporting mother rather than father parenting practices (Fletcher et al., 2011). Possible explanations for this discrepancy include varying attendance rates between parents and the nature of intervention content being less appealing to fathers (Fletcher et al., 2011). Such difficulties engaging co-parents are experienced by many parenting interventions. Future research should explore how interventions may be made more accessible and compelling for fathers and co-parents.

Intervention Effectiveness: Child Development

This review also considered the effect of parenting interventions targeting IPC on child development. Aspects of child development encompassed behavioural difficulties, mental health symptoms, and social and physical development. The interventions most successful in enhancing these outcomes generally focused on specific parenting and child management techniques delivered to groups of parents. Particularly, Triple P interventions demonstrated their highest efficacy when delivered to families that had reported escalated child behavioural issues prior to inclusion. This is congruent with earlier research that corroborates the impact of the Triple P Positive Parenting Program in ameliorating disruptive behaviours in children (de Graaf et al., 2008). The long-term mitigation of behavioural difficulties and mental health symptoms is pivotal to governmental policies committed to supporting child well-being and economic pressures on health care providers. This is pertinent given that 7% of children aged 3–17 in the USA alone have a current diagnosed behavioural disorder, and the number of children experiencing mental health difficulties has risen across nations in recent years (Centre for Disease Control & Prevention, 2023).

Intriguingly, this review provides insight into specific aspects of child behavioural difficulties that are influenced by parenting interventions. Ten articles chose to employ the ECBI, a well-validated instrument (Hukkelberg et al., 2016), as a measure of child outcomes. Significant improvements were predominantly reported on the “intensity” subscale of this measure, suggesting this aspect of child behaviour is especially amenable to change through parenting interventions. However, the systematic review also highlighted a lacuna in the literature. Despite previous meta-analyses linking IPC and child attachment security (Tan et al., 2018), no studies in this review considered this outcome. Comprehending how parenting interventions might impact attachment is crucial, given that insecure attachment has consistently associated with a plethora of negative outcomes, including an increased risk for internalising and externalising disorders (Warmuth et al., 2020). Attachment is also a focal point of many national policies. While the UK National Family Hubs programme has dedicated £50 million to develop parenting practices regarding attachment, bonding, and sensitivity (Family Hubs & Start for Life Programme, 2022), the promotion of early attachment is central to USA federal programmes (Boris & Zeanah, 2011). Further research should utilise RCT methodology to explore child attachment security between families receiving an intervention targeting IPC and a control population. Delving into the relationship between parenting interventions targeting IPC and child attachment security in this way will aid policy development by enhancing our understanding of the potential benefits such interventions can bring to children.

Intervention Delivery in the Early Years

Governmental policy, such as the UK’s “1001 critical days” report (Department of Health & Social Care, 2021), has sanctioned the early years as a key period of child development and target for intervention delivery. Surprisingly, little research has focused on the efficacy of IPC parenting interventions during these formative years. The influence of parenting interventions focusing on IPC, specifically delivered to families with children aged between 0 and 5 years, was analysed as a secondary outcome of this review. Although child age did not seem to significantly affect the results of the programmes, several interventions were identified as suitable for implementation within this age range. This is particularly important, as the transition to parenthood is known to be a period of heightened stress and vulnerability to IPC (Delicate et al., 2018), indicating a time when the need for parental support might be most acute. The Group Triple P intervention proved particularly effective in enhancing IPC, parenting behaviour, and child outcomes, and is therefore recommended for families with children aged 0–5 years old. Interestingly, no articles in this review explored the effects of interventions targeting IPC in separated couples with children under 5 years of age. Given that infancy and early childhood constitute crucial stages of development during which children may be particularly sensitive to IPC exposure (Evangelou et al., 2009), further investigation of parenting interventions during this period in a child’s life could provide invaluable insights for governmental policy, healthcare providers, and intervention execution. Research comparing post-intervention child outcomes between families with children aged 0–5 and those with children aged up to 18 years old would be particularly beneficial to identify any differences in intervention effectiveness throughout childhood and adolescence.

Limitations

While this review illuminates several crucial findings and recommendations for the implementation and evaluation of interventions, it faces several limitations. It is plausible that the inclusion criteria of the review might have inadvertently excluded some evidence that could provide a contrasting perspective on intervention effectiveness. The criteria mandated that all three outcome constructs – IPC, parenting behaviour, and child development – be evaluated. Further, the search terms did not include specific parenting intervention modalities (e.g., family systems therapy). This decision was made to focus the scope of the review on interventions directly targeting IPC. However, valuable evidence focusing on other outcomes or interventions may have been omitted. The review is also unable to comment on any possible influence of family structure on intervention outcomes. The search criteria for this review allowed participants of all family structures to be included. However, details regarding additional co-parental influences or custody arrangements between separated couples was not provided or considered within article analyses. This is important as some countries estimate that as few as 1% of separated parents have equal residence with the child (Haux et al., 2017). It is therefore feasible that identified improvements in child development may be subject to influences from the time spent with each parent and their response to intervention materials. Investigation comparing intervention outcomes across diverse family structures will enhance understanding of how multiple caregivers impact intervention outcomes.

Conclusion

IPC is a universal phenomenon which, when intense and frequent, can have detrimental long-term consequences for the family. As such, the development and provision of robust interventions is essential to support families and mitigate these adverse impacts. Nevertheless, as underscored by this review, there is a pressing need for additional research in this area. Whilst some governmental policies promote support for IPC, this is not apparent across all nations. Further understanding of intervention use in diverse, non-Western communities will support the development of such policy and national access to support for families experiencing IPC and domestic violence. Global policy development will also greatly benefit from improved understanding of how parenting interventions targeting IPC may indirectly promote child attachment security. Current policy grounded in child attachment could advance with such information, and the possible reduction in child outcomes related to improved attachment could support over-subscribed healthcare services.

This systematic review has presented several promising parenting interventions which may be effective in reducing IPC and enhancing family outcomes at various stages of family life. Unlike previous reviews, this study included research on families with children up to the age of 11 years and identified interventions that could be beneficial for younger children aged 0–5 years. However, many of the interventions considered were supported by evidence from only single evaluations meaning any conclusions drawn about their effectiveness should be viewed as provisional and requiring further investigation. Supplementary research will support the development of early healthcare provision worldwide and indicate whether delivery of parenting interventions targeting IPC during this period may substantially improve IPC and child outcomes amid a particularly vulnerable time. In particular, the Group Triple P programme emerged as the most extensively evaluated intervention and was reported to be effective in improving all three outcomes of interest (IPC, parenting behaviour, and child outcomes). On the other hand, the Parent Education Group and Couple Coping Enhancement Training interventions showed no significant impact on any of the aforementioned outcomes.

In conclusion, interventions targeting IPC provide a compelling avenue to support families and improve a range of family outcomes. The results of this systematic review suggest that such interventions may provide effective support for families grappling with the challenges posed by IPC, which may in turn positively impact the demand for higher-level professional health care throughout adulthood. Although further research is necessary to deepen our understanding of the effectiveness of interventions targeting IPC, this information will be fundamental to inform recommendations for healthcare services worldwide.