A Systematic Scoping Review on the Transition of Under-3-Year-Old Children from Home to Early Childhood Education and Care

Abstract

This systematic scoping review aimed to identify and describe published peer-reviewed research articles on the transition of under-3-year-old children from home to early childhood education and care (ECEC) from 1 January 2013 to 19 August 2024. Both national (Idunn, Libris, Oria) and international (Academic Search Premier, ERIC, PsycInfo, Scopus, Web of Science) databases were systematically searched for relevant studies in English, Danish, Norwegian, and Swedish. A total of 20 studies met the inclusion criteria for the systematic review. The results show that the number of publications fluctuated from January 2013 to August 2024. Finland was the most represented country in the different studies, and by continent, most studies were published in Europe. The studies included diverse methodologies, such as descriptive purposes or studies exploring relationships between concepts. Eleven studies used a longitudinal design. Both qualitative and quantitative methods were represented, and data were collected from multiple informants. The studies examined multiple concepts, such as children’s adaptive behavior during the transition, the ECEC process and structural quality, child characteristics, stress, and parents’ roles and experiences. The results of this review contribute to identifying research gaps and what future research can do to increase knowledge about this topic.

1. Introduction

This systematic scoping review aims to identify and describe published peer-reviewed research articles on the transition of under-3-year-old children from home to early childhood education and care (ECEC). Internationally, an increasing number of children are attending ECEC from an early age (e.g., Council of the European Union, 2019; Dalli & White, 2017; OECD, 2021). Many of these children experience a change from being at home with their primary caregivers to the ECEC center, where they spend a considerable number of hours with new caregivers and peers (Council of the European Union, 2019; Fleer & Linke, 2016). In addition, children meet new environments and routines (Monk & Hall, 2017).

In this review, we define the transition from home to ECEC as the period in which children begin attending an ECEC center for the first time, including the preparatory phase, the initial separation from the parents, and the early adjustment period in ECEC. This process may span several days, weeks, or months, depending on the ECEC practices and the needs of the children (Brooker, 2008; O’Connor, 2017; OECD, 2017).

Since this transition occurs at an early age for many children, it can have implications for their development. Early childhood is a sensitive period during which brain development accelerates rapidly and experiences within the care environment profoundly affect both cognitive and emotional growth (Blakemore & Frith, 2005; French, 2019; National Scientific Council on the Developing Child, 2007). Quality caregiving, particularly in nonparental care settings, must be nurturing and responsive to support optimal brain development. Inconsistent or lower-quality care during this stage can lead to negative outcomes, which emphasizes the need for highly trained and sensitive caregivers to promote positive developmental outcomes in young children (French, 2019). A good transition from home to ECEC is important for children’s well-being and development. Positive interactions and engagement between children, peers, parents, and professional caregivers support children’s sense of belonging, involvement, and well-being during the transition (Brooker, 2008; O’Connor, 2017). A preparatory phase (e.g., attending the ECEC center for a few hours per week before the child officially starts) may help children, parents, and ECEC staff become familiar with one another. In addition, strong parent–staff collaboration and flexibility to individual children’s needs are examples of practices that can support a positive transition from home to ECEC (e.g., O’Connor, 2017).

Even though research shows the importance of good transitions and environmental support during the early years, there is limited research on the transition from home to ECEC for children under 3 years of age. Many studies focus on children aged 3 years and older, the period after the transition from home to ECEC, the transition from an intervention or health care system to ECEC (e.g., children at risk or with disabilities), or the transition to primary school (e.g., with a focus on school readiness, which is formalized in policy and embedded in educational systems (e.g., Gath et al., 2024; Hartle et al., 2023; O’Connor, 2017; OECD, 2017; White et al., 2020).

2. Research Questions

Considering the increasing number of young children in ECEC, the increasing amount of time that young children spend in ECEC, and the potential effects of early transitions on children’s well-being and development, this systematic scoping review focuses on the transition of under-3-year-old children from home to ECEC. This study provides an overview of what is known about these children’s transition from home to ECEC, identifies knowledge gaps, and provides a basis for further research on this topic.

This study examines the following research questions:

• How many peer-reviewed research articles have been published on the transition of under-3-year-olds from home to ECEC, and what are the characteristics of these studies in terms of their year of publication, country, continent, and purpose?
• Which methodologies have been used in peer-reviewed research articles that have been published on the transition of under-3-year-olds from home to ECEC?
• Which concepts have been examined in peer-reviewed research articles that have been published on the transition of under-3-year-olds from home to ECEC?
• Which findings and implications do peer-reviewed research articles present on the transition of under-3-year-olds from home to ECEC?

3. Materials and Methods

To address the research questions above, we followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 guidelines (Page et al., 2022; Peters et al., 2020; Tricco et al., 2018). In addition, we chose to limit our search to the past 10 full years, based on previous studies indicating that robust evidence can be obtained by restricting the search period to approximately 10 to 15 years (e.g., Furuya-Kanamori et al., 2023). In addition, ECEC policy, practices, and children’s attendance numbers have evolved significantly over the past decade (e.g., Council of the European Union, 2019; Dalli & White, 2017; OECD, 2021), which may render older publications less representative of current practices.

3.1. Inclusion Criteria

During our database search, we used the following inclusion criteria to find relevant studies:

Topic: The transition from home to ECEC.

Population: Children under 3 years of age.

Time of publication: Between 2013 and 2024.

Publication type: Peer-reviewed research article.

Publication language: English, Norwegian, Swedish, or Danish.

Following these criteria, sources were not included when they violated at least one criterion. In addition, a source’s full text should be accessible to the authors.

3.2. Literature Search

We used the population–concept–context (PCC; Peters et al., 2020) framework to define our search strings. Although we were interested in the transition from home to ECEC for children under 3 years of age, we did not include “home” in our search strings, as we found many irrelevant hits when doing so (i.e., more than 10,000 irrelevant hits). Table 1 shows the search strings used in English, Danish, Norwegian, and Swedish.

Table 1. Search strings applied in the database search.

PCC (Population, Concept, Context)	Search String— English	Search String— Danish	Search String— Norwegian	Search String— Swedish
Children under 3 years	toddler* OR 0–3 OR “children under 3 years old” OR “children under 3” OR “young* child*”	børn* OR småbørn OR vuggestuebørn OR “1–3 år”	småbarn OR “små barn” OR “1–3 åring*” OR “ettåring*” OR “ett-til-treåring*”OR “de yngste barna” OR “de minste barna”	barn* OR “små barn*” OR “yngre barn*”
Transition	transition* OR “transition period” OR “transition phase” OR starting* OR “starting period” OR “starting phase	overgang* OR modtakelse OR indkjøring	“foreldreaktiv tilvenning” OR “start i barnehagen” OR tilvenning OR innkjøring OR oppstart OR overgang OR “sammenheng mellom hjem og barnehage”	inskolning* OR “aktivt föräldraskap” OR uppstart*
ECEC	ECEC* OR ECE* OR “ECEC center” OR “ECE center” OR “ECEC centre” OR “ECE centre” OR daycare OR “day care” OR “daycare center” OR “daycare centre” OR “day care center” OR “day care centre” OR childcare* OR “child care*” OR “childcare center*” OR “child care center*” OR “childcare centre*” OR “child care centre*” OR “centerbased care” OR “centrebased care” OR “centerbased childcare” OR “centrebased childcare” OR “centerbased child care” OR “centrebased child care” OR “center-based childcare” OR “centre-based childcare” OR “center-based child care” OR “centre-based child care” OR preschool* OR pre-school* OR kindergarten* OR “early childhood education” OR “early childhood education and care” OR crèche* OR creche* OR nurser* OR “day nurser*” OR “nursery school*” OR “infant school*” OR playschool* OR “play school*” OR “pre-primary school*”	børnehave* OR vuggestue* OR dagpleje*	barnehage OR småbarnsavdeling OR småbarnsgruppe	førskolan OR dagis*

Searches were performed in both national (Idunn, Libris, Oria) and international (Academic Search Premier, ERIC, PsycInfo, Scopus, Web of Science) databases. Appendix A presents the full search strategies, filters, and limits used for each database. The final search was conducted independently by three researchers on 19 August 2024. Table 2 shows the hits per database.

Table 2. Overview of databases searched and hits per database.

Source	Date	Hits
Academic Search Premier	19 August 2024	319
ERIC	19 August 2024	359
Idunn—Danish	19 August 2024	10
Idunn—Norwegian	19 August 2024	36
Idunn—Swedish	19 August 2024	1
Libris—Swedish	19 August 2024	1
Oria	19 August 2024	819
PsycInfo	19 August 2024	329
Scopus	19 August 2024	1159
Web of Science	19 August 2024	776
Total		3809

3.3. Screening Process

The aim of the screening process was to exclude studies that did not meet the inclusion criteria. Rayyan (Ouzzani et al., 2016) software was used during the screening process to code and report on the included and excluded studies. Both the title and abstract screening, as well as the full-text screening, were conducted independently by pairs of authors. As seven authors were involved in the study, the tasks were equally divided into seven portions, ensuring that each was reviewed by two authors working independently of each other. Following the independent (abstract and full text) screenings, any discrepancies or conflicts in the evaluations were discussed and resolved through consensus between the two assigned authors. This approach ensured that all sections of the study received a thorough assessment. Figure 1 presents the PRISMA flowchart of the identification, screening, and inclusion of studies.

Figure 1. PRISMA flowchart presenting the identification, screening, and inclusion of studies.

3.4. Data Extraction

The data extraction for the 20 included studies was performed by the first and second authors. Both authors filled out Appendix B independently. In cases of conflict, the two researchers had a discussion to reach a joint decision. The final data consisted of study characteristics (i.e., year of publication, country, continent, and study purpose), methodological approaches (i.e., research methods, study designs, data collection methods), sample characteristics (i.e., sample of interest, sample size, informants), concepts, findings, and implications. We use the term “concepts” to refer to the key ideas or constructs that were the focus of examination in the included studies: that is, for example, the psychological, social, or developmental phenomena being explored (e.g., ECEC process quality, staff–child attachment). By “concepts”, we do not mean general topics (e.g., transition to ECEC) or emergent themes from qualitative analysis, but rather the specific constructs or variables that studies aimed to define, measure, or explore in depth.

4. Results

After the database search and screening process, we found a total of 20 studies that met all the inclusion criteria. Appendix B provides an overview of the included studies on the transition of under-3-year-old children from home to ECEC in the 2013–2024 period. Note that professional caregivers are referred to differently in some studies listed in Appendix B, such as ECEC teacher or preschool teacher. This is because we aimed to stay as close as possible to the original wording used in each study.

4.1. Characteristics of the Studies

Year of publication: Figure 2 presents the number of studies that were published each year from the 1 January 2013 to 19 August 2024.

Figure 2. Number of studies addressing the transition of under-3-year-olds from home to ECEC from 1 January 2013 to 19 August 2024 (n = 20).

The number of publications addressing the transition of under-3-year-olds from home to ECEC varied during this period. There was a peak in 2014 and 2023, when 40% of the included articles were published, whereas no articles were published in 2013 and 2017.

Country and continent: Figure 3 shows the number of studies conducted in different countries. By country, Finland was the most represented in the studies considered in this review, accounting for 20% of the included articles. By continent, most studies were conducted in Europe (13 studies, 65%), followed by North America (four studies, 20%), Asia (two studies, 10%), and South America (one study, 5%).

Figure 3. Number of studies conducted in different countries.

Study purpose: Most studies aimed to explore the relationships between different concepts (11 studies, 55%), followed by descriptive studies (seven studies, 35%), and two studies (10%) that aimed to develop a method. Examples of examined relationships between concepts include children’s stress, child characteristics, and childcare quality. Other studies explored how different introduction models (i.e., preparation, child–adult ratios, length, intensity, and flexibility to the needs of child and family) might influence child adjustment and family–staff relationship building. The descriptive studies examined, for example, children’s behavior during the transition, centers’ practices during the transition, professional caregivers’ perspectives, and parents’ coping strategies and experiences. Two studies focused on developing and testing the applicability of a pedagogical documentation tool designed for use during the first months in ECEC.

4.2. Methodological Approaches

Research methods: Eleven studies (55%) were qualitative, seven (35%) were quantitative, and two (10%) used a mixed-methods approach

Study designs: Eleven studies used a longitudinal design, while different studies employed case study designs (four studies) or phenomenological approaches (two studies). All other study designs were represented one time (i.e., view study, observation study, ethnography, cross-sectional, comparative, and mosaic approach). Note that because of the multiple designs that are applied in some studies, the number of studies in this overview was greater than 20.

Data collection methods: The studies used multiple methods to collect their data (16 studies, 80%). Figure 4 shows an overview of the data collection methods used. Most studies used observations (11 studies) and quantitative questionnaires (seven studies), followed by saliva samples and 1-on-1 interviews (five studies each). Note that because multimethod data collection was applied in most studies, the number of studies in Figure 4 is greater than 20.

Figure 4. Number of studies by data collection method.

4.3. Sample Characteristics

Sample of interest: In most studies, children were the sample of interest (15 studies, 75%). Professional caregivers were the sample of interest in five studies, followed by parents in three studies. One study included both children and professional caregivers as their sample of interest. One study included parents and professional caregivers, and another study included both children and parents as part of the sample of interest.

Sample size: Studies that had children as the sample of interest had a sample size that varied from 1 to 222 children (M = 62.3; SD = 64.9). For studies with professional caregivers as the sample of interest, the sample size varied from 4 to 535 professional caregivers (M = 145.4; SD = 222), whereas for parents, the sample size varied from 21 to 192 (M = 80.7; SD = 96.5).

Informants: Most studies had multiple informant data (15 studies, 75%). Figure 5 shows an overview of how many studies had a certain type of informant. Professional caregivers were the most represented informants (17 studies), followed by children (14 studies) and parents (i.e., 10 studies with both fathers and mothers represented) or mothers (four studies).

Figure 5. Number of studies by type of informant.

There was an overlap between the informants and the sample of interest. In 14 studies, children were both the sample of interest and informants by participating in observations (nine studies) and giving saliva samples (five studies). Professional caregivers were both the informants and the sample of interest in seven studies. They provided data on how they arrange the ECEC practice (two studies), talked about their own experiences during the transition (two studies), were using a new pedagogical documentation tool (two studies), or were part of an observation (one study). Parents were both the informants and the sample of interest in three studies, where they talked about their coping strategies during the transition (two studies) or if they had former experience of having a child starting in ECEC (one study).

4.4. Concepts

Figure 6 shows an overview of how many studies examined a concept. Note that the number of studies in Figure 6 is greater than 20 because most studies examined multiple concepts. Children’s adaptive behavior during the transition and ECEC process quality (e.g., staff–child relationship, interactions between children in the group) were studied the most (seven studies). They were followed by concepts such as child characteristics (e.g., age, gender, temperament), ECEC structural quality (e.g., toys, staff experience), and stress (five studies). Parents’ roles and experiences were also mentioned in different studies (e.g., staff–parent relationship, mother–child attachment, maternal worries, parents’ coping strategies, family demographics).

Figure 6. Number of studies that examined concepts.

4.5. Findings and Implications

Appendix B presents the findings and implications of each study. The findings and implications are presented on the basis of the outcome variable of interest in each study, such as children’s stress, children’s adaptive behavior, ECEC quality, child characteristics, and parents’ roles and experiences.

Five longitudinal studies examined children’s stress as an outcome variable during the transition from home to ECEC, with a focus on cortisol levels as a physiological indicator of stress (Ahnert et al., 2023; Albers et al., 2016; Bernard et al., 2015; Drugli et al., 2023; Nystad et al., 2021). Despite being conducted across different cultural and educational contexts—Austria, the Netherlands, the United States, and Norway—these studies consistently revealed that the transition to ECEC is a stressful experience for many young children, particularly during the initial period of separation from parents. The findings emphasize the universal nature of the challenges faced by children during this critical transition period as they navigate the emotional and social demands of separating from their parents and the familiar comfort of home (Ahnert et al., 2023; Albers et al., 2016; Bernard et al., 2015; Drugli et al., 2023; Nystad et al., 2021). For example, Ahnert et al. (2023) conducted their study in Austria and identified four distinct cortisol profiles in young children during the transition. The highest stress levels were observed at the start, especially among younger children and those whose mothers stayed for extended periods during entry. The findings highlighted the importance of secure attachment relationships both at home and in ECEC for justifying stress during this transition. Small group sizes and larger age differences within groups were initially beneficial for reducing stress, but as children adjusted, larger groups and smaller age differences facilitated peer interactions and social inclusion, further easing stress. Similarly, Albers et al. (2016), focusing on infants from families with a high socioeconomic status (SES) in the Netherlands, reported that cortisol levels peaked sharply during the first month of ECEC and gradually declined over subsequent months, although they remained consistently higher on ECEC days than on home days. This study revealed that individual differences, such as a child’s temperament and maternal caregiving quality, influenced stress responses, with children of sensitive mothers or children with difficult temperaments showing higher cortisol levels. Bernard et al. (2015) conducted their study in the United States with children aged 0–8 years (including data on age groups such as 0–18 months and 18–36 months) and explored how cortisol patterns changed over a 10-week transition period. They reported that cortisol levels consistently rose from midmorning to afternoon on ECEC days, in contrast to the typical diurnal decline observed at home. While midmorning cortisol levels gradually declined over the course of 10 weeks, reflecting some adaptation, the persistence of elevated afternoon cortisol levels suggested that the social and environmental demands of ECEC, including peer interactions and group dynamics, continued to elicit stress responses. In Norway, Drugli et al. (2023) investigated toddlers during their transition to ECEC and reported that cortisol levels peaked during the second week of separation from parents. While stress levels gradually decreased and stabilized by the three-month mark, parents and professional caregivers reported that toddlers exhibited emotional reactivity and tiredness at home during the initial weeks. This study emphasized the importance of collaborative efforts between parents and professional caregivers to support children during this period, including creating a “caring triangle” and offering emotional support both at home and in ECEC. Similarly, Nystad et al. (2021), who also conducted their study in Norway, reported that cortisol levels increased significantly during the separation phase, peaking in the second week of entry into ECEC. Although stress levels declined over time, they remained higher than they did in the accompanied phase even after 4–6 weeks, highlighting the ongoing adaptation challenges faced by toddlers. This study suggested that shorter ECEC days during the separation phase and providing flexible parental leave could support children’s emotional adjustment.

Other studies focused on children’s adaptive behavior during the transition from home to ECEC (McDevitt & Recchia, 2022; Picchio & Mayer, 2019; Revilla et al., 2024a, 2024b; Tebet et al., 2020). These studies had qualitative approaches, which, in various ways, emphasize that the transition is not something that happens by drop-off but, rather, is a long process in which children co-create with their peers, parents, and professional caregivers. The structural quality of ECEC centers also plays an important role in this process (McDevitt & Recchia, 2022; Picchio & Mayer, 2019; Revilla et al., 2024a, 2024b; Tebet et al., 2020). Observations of children in ECEC centers in Brazil, the United States, and Finland highlight the complexities of children’s lives in ECEC and the abilities that children have to interact from an early age (McDevitt & Recchia, 2022; Revilla et al., 2024a, 2024b; Tebet et al., 2020). However, the preconditions for children’s adaptability are influenced by their home settings and their cultural background, that is, whether children’s family belongs to a minority group (for instance, being a migrant family) and speaks a language that is different from the language that is spoken in the ECEC center. These children may experience extra challenges when starting in ECEC (Picchio & Mayer, 2019). They have to settle into an ECEC center and into a new language community, which makes the transition a period of challenges, and children can be overwhelmed, to which they might react differently. Professional caregivers’ knowledge of and concern for these children are important for supporting these children when they settle into a new peer group (Picchio & Mayer, 2019).

In addition to the importance of ECEC structural quality, multiple studies had ECEC process quality as an outcome of interest, and mainly focused on attachment and relationships between the child(ren), parents, and professional caregivers. The relevance of the amount of time for attachment, gender differences, and individual and group characteristics are presented (Ereky-Stevens et al., 2018; Klette & Killén, 2019; Macagno & Molina, 2020; Schärer, 2018; Swartz & Easterbrooks, 2014). The role of parents, professional caregivers, and child characteristics in the parent–professional caregiver relationship was examined in a quantitative study conducted in the United States (Swartz & Easterbrooks, 2014). This relationship and communication prior to the transition showed that parents viewed care more positively when they knew each other and if the parents were less anxious. Professional caregivers with knowledge of children’s development communicated more frequently with parents, and they also communicated more with parents whose children had an easy temperament (Swartz & Easterbrooks, 2014). A qualitative study from Norway conducted by Klette and Killén (2019) on daily separations and reunions of children with their mothers in the morning and afternoon revealed that toddlers struggled with separation anxiety in different phases and in different ways after one month in ECEC, especially when few professional caregivers were present. Another qualitative study (Schärer, 2018), conducted in Canada, revealed that professional caregivers are most concerned with their professional roles and that their interpretations of “professionalism” influence not only the elements of the center that are more organizational and structural, such as schedules and shifts, but also professional caregivers’ relationships with parents and children. In contrast to what might be considered attachment and relational approaches to caring, professional caregivers were concerned that close attachment relationships are unhealthy and that they might result in overattached children, which can make children dependent on one particular professional caregiver. The challenge of maintaining a balance between being professional and seeking harmony with the individual child and the whole group was also found in this study (Schärer, 2018). A longitudinal study from Austria (Ereky-Stevens et al., 2018) measured attachment security at three points over the course of toddlers’ first four months in ECEC. This study focused on professional caregivers’ sensitivity during dyadic interactions, both with the individual child and in group situations. The study also investigated whether attachment security differs between boys and girls. Attachment security with professional caregivers was relatively low in dyadic interactions, and girls were more securely attached to their professional caregivers than boys were. Additionally, children who were in a group with professional caregivers that scored higher on group-related sensitivity showed greater attachment security (Ereky-Stevens et al., 2018).

A qualitative longitudinal study (Macagno & Molina, 2020) conducted in Italy examined the relationship between children and their caregivers using the adapted version of the PAD, Professional Caregiver Attachment Diary (PCAD), as a method. This study revealed that strong child–professional caregiver relationships developed within the ECEC center. After two and four months, the results revealed a significant decrease in children’s avoidant and resilient attachment behaviors. While secure attachment behavior did not increase, behaviors such as non-distress showed an upward trend. This finding suggests that children may feel increasingly secure over time (Macagno & Molina, 2020).

Other studies focused more on parents’ roles and experiences with their children’s transitions. Again, these studies were performed in various contexts and cultural settings; however, the common thread is that parental involvement in the transition period has positive results for the security of the child and for parent–professional caregiver long-term cooperation. A qualitative study from China (Lam, 2014) revealed that parents have three ways of handling children’s stress during transition periods: soothing the farewell situation, approaching the underlying reason for their children’s distress, and choosing a hard approach, with the expectation that children will learn to cope by themselves. Professional caregivers should be aware of these approaches and encourage parents to deal with the underlying reason for transition stress (Lam, 2014). One example of such a bridge between home and ECEC is provided in a Finnish study that used an artifact-based documentation method that enabled parents to talk and engage concerning their ECEC life and professional caregivers to understand children’s home situation (Rintakorpi et al., 2014). A similar implication is suggested in other Nordic studies. That is, professional caregivers should pay attention to parents’ experiences with the transition. For example, a Finnish study revealed that professional caregivers benefit from being aware that the transition may also cause stress for parents. Finding ways to understand and acknowledge their experience may enhance the transition experience for all involved (Mellenius et al., 2023). A Swedish study revealed that parent active models may provide a less stressful experience for children, professional caregivers, and parents. In parent active models, both the parent(s) and child attend the ECEC center for a full day over a period of 3 to 5 days. This allows the parent(s) to observe what happens in the ECEC center and get to know the professional caregivers better. These models can also form a better base for parent–professional caregiver cooperation in the long run (Søe et al., 2023).

5. Discussion

This systematic scoping review presents key patterns and gaps in the literature on the transition of under-3-year-old children from home to ECEC. In the following section, we discuss the main findings in relation to study characteristics, methodological trends, conceptual focus, and reported outcomes. This will be discussed in relation to other studies.

5.1. Characteristics of the Studies

Although an increasing number of under-3-year-olds spend a considerable amount of time in ECEC internationally (e.g., Council of the European Union, 2019; Dalli & White, 2017; OECD, 2021) and given the importance of the environment for children’s current and later well-being and development (Blakemore & Frith, 2005; French, 2019; National Scientific Council on the Developing Child, 2007), the number of published peer-reviewed research articles on the transition of under-3-year-olds from home to ECEC fluctuated from 1 January 2013 to 19 August 2024.

The 20 studies included in this review were conducted in 11 different countries and four different continents. This finding underlines the relevance that these studies have for many countries (e.g., OECD, 2021). Two of the Finnish studies were written by the same four authors and used data from the same research project (Revilla et al., 2024a, 2024b). In Norway, three authors contributed to two different studies; however, these were based on separate research projects (Drugli et al., 2023; Nystad et al., 2021). In Austria, one author was involved in two studies that used data from the same research project (Ahnert et al., 2023; Ereky-Stevens et al., 2018).

All 20 studies were written in English. This finding might be due to local or national policies, where researchers are encouraged to publish in English (e.g., Solberg & Wendt, 2021), as well as researchers’ own interest in the internationalization of research and the relevance of the topic (e.g., OECD, 2021).

The study purpose of 11 of the 20 studies was to explore relationships between different concepts of young children’s transition from home to ECEC. Other studies were descriptive, with the authors describing concepts of young children’s transition from home to ECEC but also focusing on practices and professional caregivers’ and parents’ perspectives and experiences. Two studies sought to develop a method that can be used when young children start in ECEC. This pattern does not correspond with some national research, such as in Scandinavia from 2018 to 2023, where most studies were descriptive, followed by studies exploring relationships (Guldbrandsen et al., 2023, 2024, 2025). We argue that there might be a trend where newer research is increasingly focusing on exploring relationships rather than being descriptive.

5.2. Methodological Approaches

Both quantitative and qualitative research methods were used to study the transition of under-3-year-olds from home to ECEC. Only two studies used mixed methods. Slightly more than half of the 20 studies had a longitudinal design (11 studies), and most studies used multiple methods (16 studies) to collect their data. It is a strength that both quantitative and qualitative research methods were used. Qualitative research can be used to describe the transition from home to ECEC and how children, parents, or professional caregivers experience this transition (e.g., Bang, 2014; Lam, 2014; McDevitt & Recchia, 2022; Schärer, 2018). Quantitative research can be used to explore the relationships between different concepts that might impact the transition from home to ECEC and the experiences of those involved (e.g., Ahnert et al., 2023; Ereky-Stevens et al., 2018; Nystad et al., 2021). Mixed-methods approaches can be used to explore changes in cortisol levels over time while also gathering parents’ and professional caregivers’ perceptions of the child’s adjustment to ECEC (e.g., Drugli et al., 2023). In addition, combining surveys and interviews can help in examining the types of introduction models used, as well as perceptions of parent–staff relationships and children’s adjustment (e.g., Søe et al., 2023). A longitudinal design is a strength, as such a design can be used to examine and compare potential effects over a longer period. The use of multiple methods is also a strength because it provides more insight into the concepts related to the transition from home to ECEC and the experiences of those involved (e.g., McDevitt & Recchia, 2022; Rintakorpi et al., 2014). The most commonly used data collection methods were observations and quantitative questionnaires.

5.3. Sample Characteristics

Most studies (15 studies) had children as their sample of interest, with a mean of 62.3 children who participated in the study. The sample sizes for professional caregivers and parents were larger, with means of 145.4 professional caregivers and 80.7 parents. Although most studies had children as their sample of interest, most studies used data from multiple informants. This is a strength, as these data provide information about children’s transition from home to ECEC from multiple perspectives. However, the “voice of children” is lacking in many studies because most studies that use children as informants collect data from them by using observations and saliva samples (e.g., Ahnert et al., 2023; Nystad et al., 2021). Parents and professional caregivers are used to participate in interviews and complete questionnaires about the child(ren) (e.g., Bang, 2014; Lam, 2014). The lack of the “voice of children” might be explained by the ethical, technical, and methodological challenges that might be faced when asking for young children’s experiences (Sumsion et al., 2011). However, there are methods, such as the dialogical communications method, that emphasize the child’s perspective by trying to obtain knowledge about how the world looks through the child’s eyes and that take the “voice of the child” seriously (Gamst, 2017). Another method can be the use of vignettes, which are short descriptive narratives based on real-life observations, describing children’s experiences during transitions. A vignette can, for example, describe how an infant responds emotionally and socially in a situation. These vignettes can be used to start a dialogue between parents and professional caregivers about what happened in that situation. Although this method does not include the “voice of children” literally, it presents the children’s experiences, preferences, and feelings when they cannot express themselves verbally yet (e.g., Herold et al., 2022; White et al., 2022b).

5.4. Concepts

Multiple studies (seven studies) examined children’s adaptive behavior during the transition and ECEC process quality. Other concepts that were examined in multiple studies were ECEC structural quality, child characteristics, stress, and parents’ roles and experiences. These concepts were often examined together in the same study. For example, Albers et al. (2016) examined how stress levels were influenced not only by child characteristics such as temperament but also by the quality of maternal behavior and ECEC. Other studies (Ahnert et al., 2023; Bernard et al., 2015; Nystad et al., 2021) also examined the relationships among children’s stress levels, child and family characteristics, and ECEC quality. Children’s adaptive behavior during the transition was also examined in studies that focused on different introduction models to compare how these models might influence children’s adjustment and parents–staff relationship building (Søe et al., 2023). The study of Rintakorpi et al. (2014) focused on the effectiveness (content and process) of a pedagogical documentation tool for understanding the child during transition. Differently, the study of Picchio and Mayer (2019) focused more on children from migrant families to examine children’s adaptive behavior during the transition.

The focus on children’s adaptive behavior, the ECEC process and structural quality, child characteristics, stress, and parents’ roles and experiences is in line with national and international ECEC policies. This is because there is an increasing focus on children’s well-being, development, ECEC quality, and family background (e.g., European Commission/European Education and Culture Executive Agency/Eurydice, 2019; Norwegian Directorate for Education and Training, 2017; OECD, 2017, 2018, 2019). However, few studies have examined the collaboration between parents and ECEC staff during the transition from home to ECEC over a longer period. The studies on parent–staff collaboration presented in this review collected data at one time point to examine how the parents–staff relationship is influenced by a certain transition model (Søe et al., 2023) or by child, family, and staff characteristics (Schärer, 2018; Swartz & Easterbrooks, 2014). In addition, few studies have examined professional caregivers’ own experiences when working with children and parents during the transition from home to ECEC (Schärer, 2018).

5.5. Findings and Implications

Taken together, the 20 peer-reviewed research articles included in this review highlight the multifaceted responsibilities of parents, professional caregivers, and ECEC systems in supporting children during the critical transition from home to ECEC. Across the studies, emphasis is clearly placed on the need for gradual and well-structured transition routines. Activities such as pre-enrollment visits (i.e., visiting the center in the weeks or months before the child starts in ECEC) and introductions to professional caregivers can help children familiarize themselves with the new environment and may ease their adjustment to ECEC (Drugli et al., 2023; Nystad et al., 2021; Revilla et al., 2024b). Collaborative efforts between parents and professional caregivers are crucial in creating a “caring triangle”, which ensures the continuity of emotional support and care both at home and in the ECEC setting (Drugli et al., 2023; Rintakorpi et al., 2014; Swartz & Easterbrooks, 2014; Søe et al., 2023).

Caregiver sensitivity and responsiveness are central to reducing children’s stress during this period. Observing signs of discomfort and providing appropriate comfort and reassurance for children are essential for fostering security in children (Ahnert et al., 2023). However, quick responses to children’s emotions should not be the sole focus. Long-term solutions should also be found, such as determining why the child is crying (Bang, 2014). In addition, smaller group sizes and greater age diversity help children in the transition period and ease their stress by allowing for more individualized attention. As children adapt, larger groups and peer interactions within more homogenous settings can further promote social inclusion and reduce stress (Ahnert et al., 2023). Structured routines, shorter ECEC hours during early weeks, and calm, quiet activities during afternoon hours are also beneficial for supporting children’s emotion regulation (Drugli et al., 2023; Klette & Killén, 2019; Nystad et al., 2021). Parents play an equally important role by offering emotional closeness and soothing activities at home to support recovery from ECEC-related stress (Nystad et al., 2021). In addition, both parents and professional caregivers should be empowered in their coping strategies for dealing with children’s various transition-related challenges so that they can increase their understanding and better support both children and parents (Lam, 2014; Mellenius et al., 2023; Revilla et al., 2024a, 2024b; Swartz & Easterbrooks, 2014).

Individualized care is another key theme, as children’s stress responses vary based on their temperament, attachment style, and prior ECEC experiences (Albers et al., 2016; Bernard et al., 2015; Revilla et al., 2024b). Early identification of children who struggle with transitions allows professional caregivers and parents to provide targeted interventions, ensuring that these children receive the support that they need to adjust. Persistent maternal anxiety during the transition period, as noted by Ahnert et al. (2023), can exacerbate children’s stress, further emphasizing the importance of supporting parents during this time. In addition, the use of pedagogical documentation as a tool to better understand the child is recommended. Such documentation provides more information about the child during the transition for both the parents and professional caregivers (Rintakorpi et al., 2014).

Future research directions highlight the need for studies with larger and more diverse samples, particularly those including children from low socioeconomic or other cultural backgrounds, to explore the role of ECEC quality in stress regulation and in dealing with challenges during the transition (Albers et al., 2016; Picchio & Mayer, 2019). Longitudinal studies are also recommended to track cortisol patterns, developmental trajectories, and the effects of ECEC experiences over extended periods (Bernard et al., 2015). Examining specific factors such as professional caregiver–child relationships, peer interactions, and daily routines can provide deeper insights into stress regulation during transitions (Bernard et al., 2015; Drugli et al., 2023; Ereky-Stevens et al., 2018; Schärer, 2018). Measures that can capture the quality of group-related interactions should be developed (Ereky-Stevens et al., 2018). Preferably, a measure should be developed that can distinguish between children’s 1-on-1 interactions with other children and with the professional caregiver, the child’s experiences of the professional caregiver’s interaction with the peer group, and the strategies of the professional caregiver with the peer group, as also suggested by Van Schaik et al. (2014). Additionally, the measurement of how children’s behavior changes in different situations and ECEC quality is of interest for future research (McDevitt & Recchia, 2022; Macagno & Molina, 2020; Revilla et al., 2024b; Søe et al., 2023; Tebet et al., 2020). The collection of additional cortisol samples throughout the day and the observation of children’s behaviors both at home and in ECEC are also critical for a more comprehensive understanding of stress responses (Albers et al., 2016).

Taken together, these findings call for policies and practices that prioritize gradual transitions, caregiver sensitivity, and parent–professional caregiver collaboration to optimize children’s well-being during this sensitive adjustment period. The insights provided by these studies contribute to shaping a more supportive framework for home-to-ECEC transitions, ultimately fostering healthier developmental outcomes for young children.

6. Limitations

Although an extensive systematic search procedure was followed, this study has some limitations. It cannot be guaranteed that all published peer-reviewed research articles on the transition of under-3-year-olds from home to ECEC were identified. The search strings might not cover all potential terms that can describe ECEC, transition, and under-3-year-olds in all four different languages. In addition to the search strings, the inclusion criteria might have caused some studies to be not identified or to have been excluded. For example, only published peer-reviewed research articles were included. We wanted to ensure that all the studies were peer-reviewed, as this is not always clear for all types of publications, such as books and reports. In addition, the full texts of other publication types are often less accessible than those of research articles. This might have caused us to miss relevant peer-reviewed books (e.g., White et al., 2022a). We also excluded studies in which the age of the children was not reported. This might have caused some studies to be excluded even though they reported on the transitions of children under the age of 3 years. Another limitation of this study is the search for studies written in English, Norwegian, Swedish, and Danish. It is possible that relevant studies were published in other languages as well, but we had to limit ourselves to our language competencies, allowing us to check for interrater reliability between the different researchers of this study when screening the publications. In addition, we limited our search to the period from 1 January 2013 to 19 August 2024. There might be publications from before 2013 that are still relevant, but since ECEC practice, policy, and attendance numbers are developing quickly, we limited our search to the 2013–2024 period. The last limitation might be that we did not conduct a quality assessment of the studies included, which means that we did not consider whether the studies reported validity, reliability, and transparency or what the level of quality was.

7. Implications

Although this study has some limitations, it provides an overview of what is known about the transition of under-3-year-olds from home to ECEC and what the implications are for further research on this topic. Future research can use more mixed methods because both quantitative and qualitative methods have strengths and limitations. Mixed methods can help in comparing different types of data from the same sample to gain more insight into what is happening and is being experienced by multiple informants during the transition from home to ECEC. In addition, more focus should be placed on “children’s voice”, as most studies use children as informants by conducting observations or collecting saliva samples. Parents and professional caregivers provided answers for children in the studies included. While these adult perspectives are crucial, they may not fully capture the experiences and internal states of the children involved. Given the limitations of direct interviews with young children, future studies should incorporate methods such as interactive conversations to engage children in a manner that is both age-appropriate and conducive to expressing their own views and emotions.

Future research might also conduct intervention studies to compare which introduction models might work best for children, parents, and ECEC staff. New or further developed tools and programs might be tested to determine what can support all stakeholders best. The collaboration between parents and staff can also be studied over a longer period instead of at one time point. In addition, the experiences of professional caregivers might be studied in greater depth in terms of how they cope with the transition period from home to ECEC and how this affects them and their colleagues. Finally, children from migrant families and children with disabilities should be studied more in the future. These children are often absent in samples, are not part of any intervention, or do not receive any extra support. These children may face extra challenges during the transition from home to ECEC; therefore, they should be included more in future research.