EFFECTS OF KANGAROO MOTHER CARE ON MATERNAL MOOD ...

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EFFECTS OF KANGAROO MOTHER CARE ON MATERNAL MOOD AND INTERACTION PATTERNS BETWEEN PARENTS AND THEIR PRETERM, LOW BIRTH WEIGHT INFANTS: A SYSTEMATIC REVIEW EIRINI ATHANASOPOULOU

Lancaster University, United Kingdom JOHN R.E. FOX

Manchester University, United Kingdom The birth of a premature infant can have adverse effects on the mood of mothers and on the interaction patterns between parents and their preterm babies. The aim of the present systematic review was to examine whether the Kangaroo Mother Care (KMC) intervention can attenuate these adverse psychological effects of a premature birth by ameliorating negative maternal mood and/or promoting more positive interactions between preterm infants and their parents. The results showed that although findings of studies were inconclusive, there is some evidence to suggest that KMC can make a positive difference on these areas. Specifically, it was found that KMC can improve negative maternal mood (e.g., anxiety or depression) and promote more positive parent–child interactions. Limitations and directions for future research are discussed.

ABSTRACT:

RESUMEN: El nacimiento prematuro de un infante puede tener efectos adversos en el humor de las madres y en los patrones de interacción entre los padres y sus bebés prematuros. La meta de la presente revisión sistemática fue examinar el hecho de si la intervención del Cuidado Maternal Estilo Canguro (KMC) puede atenuar estos efectos sicológicos adversos de un nacimiento prematuro por medio de mejorar el negativo humor maternal y/o promover interacciones más positivas entre los infantes prematuros y sus padres. Los resultados mostraron que aunque las revelaciones de los estudios eran inconclusas, hay alguna evidencia para sugerir que KMC puede hacer una diferencia positiva en estas a´ reas. Espec´ıficamente, se encontró que KMC puede mejorar el humor maternal negativo (tal como la ansiedad o la depresión) y promover interacciones madre-infante más positivas. Se discuten las limitaciones y las directrices para la futura investigación. ´ ´ RESUM E:

La naissance d’un nourrisson prématuré peut avoir des effets défavorables sur l’humeur des mères et sur les patterns d’interaction entre les parents et leurs bébé prématurés. Le but de cette revue systématique e´ tait d’examiner si l’intervention Soin de la Mère Kangourou (abrégé KMC en anglais, pour Kangaroo Mother Care) peut atténuer ces effets psychologiques défavorables sur la naissance prématurée, en améliorant l’humeur maternelle négative et / ou en promouvant des interactions plus positives entre les nourrissons prématurés et leurs parents. Les résultats montrent que bien que les résultats des e´ tudes e´ taient sans conclusion, des preuves existent suggérant que l’intervention KMC peut faire la différence, une différence positive, dans ces domaines. De façon plus spécifique, on a e´ tabli que l’intervention KMC peut améliorer l’humeur maternelle négative (telle que l’anxiété ou la dépression) et promouvoir des interactions parents-enfant positives. Les limites et les directions de recherches a` venir sont discutées.

ZUSAMMENFASSUNG: Die Geburt eines Frühgeborenen kann negative Auswirkungen auf die Stimmung der Mütter und auf die Interaktionsmuster zwischen Eltern und ihren Frühgeborenen haben. Das Ziel des vorliegenden systematischen Reviews war es, zu untersuchen, ob die ,,Kangaroo Mother Care“ (KMC) Intervention diese negativen psychologischen Auswirkungen einer Frühgeburt vermindern kann, indem die negative Stimmung der Mütter verbessert wird und/oder positive Interaktionen zwischen Frühgeborenen und deren Eltern gefördert werden. Die Ergebnisse zeigten, auch wenn die Befunde der Studien nicht eindeutig waren, dass es einige Hinweise darauf gibt, dass KMC in diesen Bereichen etwas bewirken kann. Insbesondere wurde festgestellt, dass KMC negative mütterliche Stimmung (wie Angst oder Depression) verbessern und mehr positive Eltern-Kind-Interaktionen fördern kann. Limitationen und Hinweise für die zukünftige Forschung werden diskutiert.

We thank Dr. Anna Daiches, Clinical Director and Admissions Tutor; Dr. Emma Munks, Clinical Tutor; and Dr. Maria Papastathi, Researcher in Linguistics, for their valuable comments and feedback on the article. Direct correspondence to: Eirini Athanasopoulou, Department of Clinical Psychology, Lancaster University, Whewell Building, Fylde Avenue, Lancaster, United Kingdom LA1 4YF; e-mail: [email protected]. INFANT MENTAL HEALTH JOURNAL, Vol. 35(3), 245–262 (2014) C 2014 Michigan Association for Infant Mental Health View this article online at wileyonlinelibrary.com. DOI: 10.1002/imhj.21444

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E. Athanasopoulou and J.R.E. Fox

ABSTRACT: The birth of a premature infant can have adverse effects on the mood of mothers and on the interaction patterns between parents and their preterm babies. dd:ddddddddddddddddddddddddddddddddddddddddddddddddddddddddd ddddddddddddKangaroo Mother Care (KMC)ddddddddddddddddddddddd/dddddddddddd ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd ddddddddddddddddddddddddddKMCddddddddddddddddddddddddddddddd ddddddddddddddddddKMCdddddddddddd(dddddddd)ddddddddddddddddddd ddddddddddddddddddddddddddddddddddd

* * * The birth of a premature, low birth weight baby can be a difficult experience for families. It has been suggested that mothers can experience negative emotions, anxiety, and depression by the unexpected conclusion of their pregnancy (Brisch, Bechinger, Betzler, & Heinemann, 2003; Brooten, Gennaro, Brown, & Butts, 1988; Ukpong & Fatoye, 2003; Zanardo, Freato, & Cereda, 1998) because they may have not been able to prepare themselves for separation from the baby (Korja et al., 2009). In addition, preterm babies are often born with low birth weight, which can be a risk factor for their survival and neurological development (Hack, Klein, & Taylor, 1995). This can lead to additional stress and worry related to the infant’s health for the families (Brisch et al., 2003). A premature birth also can influence the quality of early mother–infant interaction in various ways (Forcada-Guex, Pierrehumbert, Borghini, Moessinger, & Muller-Nix, 2006; Malatesta, Grigoryev, Lamb, Albin, & Culver, 1986). For example, mothers of preterm infants can be more controlling, anxious, and concerned about the infant’s health as well as less emotionally involved than are mothers of full-term infants (Forcada-Guex et al., 2006; Muller-Nix et al., 2004). Malatesta, Grigoryev, Lamb, Albin, and Culver (1986) found that mothers of preterm babies were less likely to imitate or respond to their baby’s emotional expressions, especially when babies were expressing anger or sadness. One factor that seems to play an adverse role in the development of the early dyadic relationship between mother and preterm infant is separation when the infant is placed in an incubator (Tallandini & Scalembra, 2006). Under these circumstances, the opportunities for physical proximity and touch between parent and child can be limited, and the development of child–parent attachment can be negatively affected (Feldman, Weller, Sirota, & Eidelman, 2003). It also has been suggested that separation can create a physical and emotional distance between mother and child and can enhance maternal feelings of distress and inadequacy (Stern, 1977; Tallandini & Scalembra, 2006). Research has demonstrated the challenges the neonatal intensive care unit (NICU) context can pose on mothers as they strive to establish their role in their baby’s life and their identity as a mother while having less opportunities to be with their baby around the clock (Fenwick, Barclay, & Schmied, 2008). The involvement of staff in the infant’s life can further complicate the process, as mothers can feel the need to prove their competency to staff and ameliorate possible shame related to their conflicting feelings of motherhood (Fenwick

et al., 2008; Flacking, Ewalda, & Starrin, 2007). Elimination of the negative effects of early separation has now become the focus of many interventions in NICU, and one of the developmental care interventions that is implemented as a result is Kangaroo Mother Care (KMC). KMC

KMC was introduced in 1978 in Bogota, Colombia by the pediatrician Edgar Rey (Ruiz-Peláez, Charpak, & Cuervo, 2004) as a way to solve the problem of insufficient resources in hospitals where there was a demand for incubators (Doyle, 1997). It was first used to maintain the infant’s temperature within normal range, through contact with the caregiver’s body. KMC is currently used widely in Western as well as developing countries for parent–low birth weight infant dyads, and the models of application include continuous and intermittent KMC (Nyqvist et al., 2010). Continuous KMC is commonly used in developing countries, but is also applied in some high-tech NICU (Blomqvist & Nyqvist, 2010; Nyqvist et al., 2010). It involves continuous skin-to-skin contact between mother and baby, from birth until (at least) the 40th week, ideally accompanied by breastfeeding, discharge when the infant is medically stable, and careful follow-up (Cattaneo, Davanzo, Uxa, & Tamburlini, 1998; Nyqvist et al., 2010). Intermittent KMC is commonly used in Western countries to facilitate bonding between caregivers and infants and is applied for shorter periods daily for a numbers of days (Nyqvist et al., 2010). During KMC, the infant is placed in skin-to-skin contact with the mother’s, father’s, or caregiver’s chest in a frontal position with the infant’s head turned sideways; the airway is secured so that obstruction to breathing is prevented (Nyqvist et al., 2010). To maintain appropriate body temperature, the infant may wear a hat, socks, or diaper and is usually placed under the caregiver’s clothes or covered with a blanket (Cattaneo et al., 1998; Nyqvist et al., 2010). Elastic cloth bands also can be used to maintain the infant’s position (Nyqvist et al., 2010). At the same time, it is recognized that caregivers who provide KMC should be provided with adequate support and information while education and training needs to be offered to healthcare staff (Cattaneo et al., 1998; Nyqvist et al., 2010). Finally, consistent protocols and guidelines for KMC need to be in place in healthcare facilities (Cattaneo et al., 1998; Nyqvist et al., 2010).

Infant Mental Health Journal DOI 10.1002/imhj. Published on behalf of the Michigan Association for Infant Mental Health.

Kangaroo Mother Care, Maternal Mood, and Parent−Infant Interaction

Many researchers have reported positive outcomes of KMC on the infant’s physiological state. The benefits include better cognitive development, reduction of infections and positive outcomes on sleep and crying, temperature, weight gain, heart and respiratory rates, energy expenditure and oxygenation (Dodd, 2005; Hall, & Kirsten, 2008; Ludington-Hoe, 2011; Tessier, Cristo, Nadeau, & Schneider, 2011). Moreover, positive psychological effects have been identified for infants and their families, such as positive outcomes on mother–infant interaction, maternal mood, and sense of coping (Charpak et al., 2005; Tallandini & Scalembra, 2006; Tessier et al., 2011). CONTRIBUTION OF THIS SYSTEMATIC REVIEW

The reviews that have been conducted to date on the benefits of KMC (Charpak, Ruiz-Pelaez, & de Calume, 1996; Charpak et al., 2005; Feldman, 2004; Hall & Kirsten, 2008; Kirsten, Bergman, & Hann, 2001; Nyqvist et al., 2010; Tessier et al., 2011; Whitelaw, 1990), have not focused on the aspects of mother–preterm infant interaction patterns or maternal mood. The decision to examine the effects of KMC on maternal mood and/or parent–infant interaction patterns in this systematic review is based on the fact that they constitute two important components of the infant’s early life. Specifically, maternal mood can play an important role in the development of the early mother–infant interaction, which in turn can influence the child’s later emotional expression and development, attachment pattern, behavior, and cognitive abilities (Brisch et al., 2003; Carter, Garrity-Rokous, Chazan-Cohen, Little, & BriggsGowan, 2001; Edhborg, Lundh, Seimyr, & Widstrom, 2003; Elgar, McGrath, Waschbusch, Stewart, & Curtis, 2004; Grace, Evindar, & Stewart, 2003). It also has been found that the birth of a premature baby can exacerbate feelings of distress and depression for mothers (Davis, Edwards, Mohay, & Wollin, 2003), which can have an adverse effect on their interaction with their infants (Forcada-Guex et al., 2006). The importance of the quality of the early interaction and attachment between mother and infant has been established through John Bowlby’s and Mary Ainsworth’s work. Attachment has been defined as the affectional bond that is formed between one person and a significant other, which is behaviorally demonstrated through behaviors that seek to gain and maintain proximity with the significant person (e.g., Ainsworth & Bell, 1970). Bowlby (1977) demonstrated the importance of children’s affectional bonds with caregivers, as well as the impact of childhood loss and the breaking of bonds on children’s future psychological well-being. Furthermore, in his inner working model theory, Bowlby (1973, 1980) argued that via relationships with significant others, the infant learns about the availability of others to his or her own needs. Through this process, the infant develops a sense of the self as worthy or unworthy, and the outcome of this can have lasting effects on the child’s view of self as well as on his or her ability to relate to other people (Bowlby, 1973, 1980). Considering the importance of early bonding between infants and their caregivers, the early separation of infants from their caregivers in NICU contexts can have adverse

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effects on their future psychological well-being, sense of self, and interpersonal relationships. As discussed earlier, a preterm birth can also trigger difficult feelings in parents, and early separation in NICU can have a negative effect on the parents’ perceptions of their role in their infant’s life. It therefore is important to establish whether KMC can have positive outcomes on maternal mood and early parent–infant interactions. AIM OF THIS SYSTEMATIC REVIEW

The aim of the present systematic review was to examine whether the KMC intervention can attenuate the adverse psychological effects of a premature birth (described earlier) by ameliorating negative parental mood and/or promoting more positive interactions between preterm infants and their parents. This systematic review is the first to synthesize and evaluate research findings from randomized and nonrandomized controlled trials on the effects of KMC on parent–preterm infant interaction patterns and/or maternal mood. METHOD

This systematic review was conducted following a predefined, peer-reviewed protocol. After selection, the studies were evaluated for bias in accordance with Cochrane Collaboration guidelines (Green & Higgins, 2008). Inclusion/Exclusion Criteria

The following criteria needed to be fulfilled for studies to be included in the review. Participants. Eligible studies included preterm and low birth weight infants (healthy or otherwise) and their caregivers (mothers and fathers)—biological parents or otherwise. Infants’ gestational age had to be ≤37 weeks, as infants born within this age range are considered preterm (McCarton, Wallace, Divon, & Vaughan, 1996). There was no specific cutoff point for birth weight, but eligible studies had to describe their sample as low birth weight. Participants were from various nationality backgrounds, age, education, and income ranges. Study design. Primary randomized and other controlled clinical trials that utilize a quasi-experimental design (e.g., nonequivalent groups design) were included in the review. The decision to include only controlled clinical trials was based on the premise that this design is the most suitable to examine the effects of an intervention and, in turn, to answer the research question of this review (Greenhalgh, 2006). However, randomization in studies that have examined the effects of KMC in preterm babies is not without its critiques because withholding a commonly used treatment from participants for research purposes creates ethical dilemmas. In some countries, KMC is mainly used to maintain infants’ body temperature


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(World Health Organization, 2003) and is therefore used to improve physical health, so withholding it from participants can pose ethical issues. Thus, in some studies, researchers have assigned their participants to groups according to hospital policies. Specifically, participants who were admitted to hospitals which utilized KMC were assigned to the KMC group while participants admitted to hospitals which did not use KMC were assigned to the control group (e.g., Feldman, Eidelman, Sirota, & Weller, 2002; Tallandini & Scalembra, 2006). Given that KMC was a commonly used treatment in those hospitals, the decision of researchers to not deny it to participants was justified. These studies therefore were included in the review because exclusion would compromise the accuracy of the conclusions. However, randomization versus nonrandomization was a factor to be taken into account at the quality assessment. Measures. For studies to be eligible for inclusion in the review, researchers had to have used quantifiable, standardized assessment measures such as questionnaires and/or coded observations. Studies in which researchers developed their own quantifiable measures (e.g., questionnaires) also were included, but the validity of the instrument was taken into account for the quality assessment.

All primary studies that were retrieved through the online databases were screened for suitability and relevance according to the inclusion criteria described earlier. Decisions were made based on the information on the titles and abstracts. At this stage, studies that clearly did not meet all of the inclusion criteria were excluded from the review. When a judgment could not be made by reading the abstracts, the full text was retrieved and evaluated. Thirteen studies were included in this review (see Figure 1).

Data Extraction

Data extraction was performed for each study in accordance with the guidelines for the reporting of primary empirical research studies in education (REPOSE; Newman & Elbourne, 2004). The REPOSE guidelines provide a framework of study characteristics that are important to be reported for research findings to be understood and evaluated (Newman & Elbourne, 2004). Based on this framework, the following characteristics were documented for each study: • •

Outcome measures. To be included in the review, outcomes of studies had to be related to KMC and its effects on parent–preterm, low birthweight infant interaction and/or maternal mood. Effects on these areas had to be measured directly through standardized measures, structured interviews, or coded observations.

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Publication process. All studies were published in peer-reviewed journals. •

Identification, Retrieval, and Selection of Studies

To identify all relevant published papers, the following electronic databases were searched: Academic Search Complete (ASC; EBSCO), AMED (Alternative Medicine) (EBSCO), BMJ Journals Collection, Cochrane Library, PsycArticles (EBSCO), PsycINFO (EBSCO), PubMed, ScienceDirect (Elsevier), and Web of Science. The search terms that were used to aid identification of studies were: KMC, kangaroo baby care, kangaroo holding, skin to skin contact, and skin-to-skin contact as well as stress, maternal stress, maternal anxiety, maternal depression, maternal mood, preterm baby, preterm infant, low birth weight baby, low birth weight infant, parent/mother–infant interaction, and parent/mother–infant relationship. Once all relevant studies were retrieved, their reference sections were screened for additional relevant clinical trials. Systematic and narrative reviews on the psychological benefits of KMC also were retrieved through the process described earlier, and they also were searched for additional published studies. This is a procedure that has been followed by authors of systematic reviews (e.g., Carfoot, Williamson, & Dickson, 2003; Renfrew et al., 2009).

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Structured abstract Study aims, rationale, and research questions Research design Sampling strategy/participants: sample characteristics and selection (inclusion/exclusion criteria), sample size, recruitment methods Data collection: methods/tools of data collection, who collected the data and where, reliability and validity of measures Data analysis: methods for analysis, statistical tests Results: consistency with methods used, reporting of statistical values Conclusions: consistency between results and conclusions, generalizability of findings. RESULTS AND DATA SYNTHESIS

A total of 13 randomized and nonrandomized controlled trials examining the effects of KMC on maternal mood and/or parent– preterm infant interaction were identified and retrieved.

Data Synthesis

Data on the areas of maternal mood and parent–preterm infant interaction patterns were synthesized and evaluated. Although researchers in some of the studies have investigated both areas, the findings on maternal mood and parent–infant interaction patterns will be presented separately. The main methodological characteristics and findings of studies are summarized in Table 1.



FIGURE 1.

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Flowchart of the selection process of the studies.

KMC and Parental Mood

Nine studies have examined the effects of KMC on the mood of mothers of preterm, low birth weight babies. Five of those have found significant differences between the mood of mothers in the KMC group and those in the control group (De Macedo, Cruvinel, Lukasova, & D’Antino, 2007; Feldman et al., 2002; Lai et al., 2006; Tallandini & Scalembra, 2006; Tessier et al., 1998) while four did not (Ahn, Lee, & Shin, 2010; Miles, Cowan, Glover, Stevenson, & Modi, 2006; Roberts, Paynter, & McEwan, 2000; Whitelaw, Heisterkamp, Sleath, Acolet, & Richards, 1988). Specifically, Tessier et al. (1998) reported that mothers in the KMC group felt more competent in looking after their babies and were less stressed when separated from them, as compared to mothers in the control group. At the same time, however, they reported that they felt less supported during their babies’ stay at the NICU and more socially isolated. In a similar vein, two more studies have found that mothers who performed KMC alone (Tallandini

& Scalembra, 2006) or combined KMC with relaxing music (Lai et al., 2006) reported lower stress. Moreover, Feldman et al. (2002) found that mothers in the KMC group were less depressed, as compared to mothers in the control group, and perceived their infants as more normal. However, the infants’ level of medical risk was found to be a significant factor in both groups, as mothers of infants in high risk had higher depression scores, and this was not ameliorated by KMC. Finally, De Macedo et al. (2007) reported that mothers in the KMC group felt calmer, stronger, more energetic, contented and tranquil, better coordinated, more clear-headed and quick-witted, more relaxed, attentive, proficient, friendly, and happier. In contrast, four studies did not detect significant differences in maternal mood between groups (Ahn et al., 2010; Miles et al., 2006; Roberts et al., 2000; Whitelaw et al., 1988). Methodological considerations. There were some methodological issues in the studies just mentioned that need to be considered.


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TABLE 1. Methodological Characteristics, Quality Scores, and Main Findings of Studies Study/Design/ Country

Participants

Measures

Intervention & Control Conditions

KMC group: 36 m per day BW (g): KMC = 1,152; Self-report measures on confidence looking skin-to-skin contact/unclear CG = 1,135 after the baby, knowing overall duration GA (weeks): KMC = the baby, feeling CG: Normal handling and 29.10, CG = 29.5 optimistic about the cuddling (Mother and baby Maternal ed.: unknown baby, being depressed, were clothed.); equal Maternal age: unknown feeling detached from amount of support by n = 71 dyads (mothers & baby, and feeling nursing staff as that given to infants) supported in looking the KMC group after the baby Amount of parent–infant (Whitelaw et al., 1988) skin-to-skin contact was recorded; unclear by whom Tessier et al., 1998 BW (g): KMC = 1,660; Video recordings, coded KMC group: 24-hr skin-to-skin contact using the NCAFS CG = 1,736 RCT daily/2.5–3.5 weeks (Barnard, 1975); GA (weeks): KMC = Colombia CG: Babies were in Mother’s Perception of 33.10, CG = 33.70 incubators; mothers were Premature Baby Maternal ed.: Unknown encouraged to visit and Maternal age: Unknown Questionnaire (unclear breastfeed; same care and whether standard n = 100 dyads (others & assessment or infants) follow-up as that given to developed by the KMC group investigators) No method of recording amount of parent–infant skin-to-skin contact Whitelaw et al., 1988 RCT England

Main Findings

Follow-Up

Similar scores between groups in At 6 months: Similar scores for all variables all examined variables (n.s.) (n.s.). x¯ not reported. x¯ not reported Additional measure introduced at 6 months: 48-hr diary of infant’s behavior: KMC infants cried significantly less (¯x = 25 min per day) than did CG (¯x = 38 min per day), p = .04 None At 41 weeks’ conceptual age: Delay before intervention moderating variable: KMC mothers had greater sense of competence (1- to 2-days’ delay: x¯ = .26/3- to 14 days’ delay: x¯ = .15/>14-days’ delay: x¯ = .09) CG x¯ = −.15, −.10, −.12, respectively; p = .001 KMC group had greater sensitivity (1- to 2-days’ delay: x¯ = .73/3- to 14-days’ delay: x¯ = .72/ > 14-days’ delay: x¯ = .75) CG x¯ = .71, .73, .69, respectively; p = .02 CG mothers were more stressed when separated from infants for longer (¯x = .24), as compared to KMC mothers (¯x = −.05), p = .05 KMC mothers felt less socially supported (¯x = −.10, .03, −.15) than CG mothers (¯x = −.04, .09, .32), p = .03 Need for NICU moderating variable: KMC mothers had greater sense of competence (¯x = .24 with NICU, x¯ = .14 without NICU) than CG (¯x = −.30 with NICU, x¯ = −.10 without NICU), p = .001 Mothers in both groups showed greater sensitivity when child in NICU (with NICU: KMC x¯ = .77, CG x¯ = .75; without NICU: KMC x¯ = .73, CG x¯ = .71, p = .01. Infants gave clearer cues (with NICU: KMC x¯ = .66, CG x¯ = .67; without NICU: KMC x¯ = .64, CG x¯ = .62), p = .02, and were more responsive to mothers (with NICU: KMC x¯ = .33, CG x¯ = .34; without NICU: KMC x¯ = .31, CG x¯ = .29, p = .05 (Continued)



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TABLE 1. Continued Study/Design/ Country Roberts et al., 2000 RCT Australia

Feldman et al., 2002 OCT Israel

Feldman et al., 2003 OCT Israel

Lai et al., 2006 RCT Taiwan

Participants

Measures


KMC group: 2-hr BW (g): KMC = 1,562; CG PSS-NICU (Miles, Funk, & Carlson, skin-to-skin contact = 1,481 1983), PES (Reece, daily/4 weeks GA (weeks): KMC = 31.70, 1992) CG: contact with mother CG = 31.20 through clothing & Maternal ed.: unknown blanket Maternal age (years): KMC Amount of parent–infant 26, CG 28 skin-to-skin contact was n = 30 dyads (mothers & recorded on charts, infants) unclear by whom KMC group: 1-hr BW (g): KMC = 1,245; CG Video recordings of mother–infant skin-to-skin contact = 1,289 interaction using daily/14 days GA (weeks): KMC = 30.38, the MNCS CG: No information CG = 31.82 (Feldman, 1998a), reported CRIB score: KMC = 2.29, CIB (Feldman, Amount of parent–infant CG = 2.25 1998b), BDI (Beck, skin-to-skin contact was Maternal/paternal ed. (years): 1978), NPI recorded by a nurse KMC = 14.70/14.47, CG = (Broussard & 14.11/14.55 Hartner, 1970), ICQ Maternal/paternal age (Bates, Freeland, & (years): KMC = Lounsbury, 1979), 29.63/32.29, CG = HOME (Caldwell 29.07/32.46 & Bradley, 1978) n = 146 triads (mothers, fathers, & infants) BW (g): KMC = 1,245; CG Video recordings of KMC group: 1-hr dyadic & triadic = 1,289 skin-to-skin contact interactions using GA (weeks): KMC = 30.65, daily/14 days; specialist CIB (Feldman, CG = 30.82 nurse assisting mothers in 1998b), PSI CRIB score: KMC = 2.29, KMC (Abidin, 1983), CG = 2.25 CG: No information PCSC (Johnston & Maternal/paternal ed. (years): reported Mash, 1989), KMC = 14.70/14.47, CG = Amount of parent–infant HOME (Caldwell 14.11/14.55 skin-to-skin contact was & Bradley, 1978) Maternal/paternal age recorded by a nurse (years): KMC = 29.63/32.29, CG = 29.07/32.46 n = 146 triads (mothers, fathers, & infants)

BW (g): >1,500 GA (weeks): ≤37 Maternal ed.: unknown Maternal age (years): unknown n = 30 dyads (mothers & infants)

STAI Form Y KMC group: 1-hr (Spielberger, 1983), skin-to-skin contact with Behavioural State music daily/3 days of Infants (Lai CG group: routine care in et al., 2006) incubator (no further information) Parent–infant skin-to-skin contact was observed; unclear by whom

Main Findings

Follow-Up

Similar scores for all variables (n.s.). Follow-up at 6 months only for weight gain x¯ PSS-NICU categories: KMC: 3.3, 4.0, 4.4, 4.4; CG: 3.2, 4.0, 3.4, 4.3 x¯ PES: KMC: 8.4; CG: 8.8 ES not reported

Using MNCS; BDI; NPI: KMC Follow up at 3 & 6 mothers: more positive months. At 3 months interactions: looking at infants using HOME & ICQ: (KMC x¯ = .45, CG x¯ = .31) & KMC mothers & fathers touching infants (KMC x¯ = .45, provided more CG x¯ = .26), positive affect (KMC sensitive & x¯ = .38, CG x¯ = .13), more stimulating home adaptive to infant’s cues (KMC x¯ environment, medical = 4.00, CG x¯ = 3.32), less risk n.s. factor. At 6 depressed (KMC x¯ = 6.68, CG x¯ months using CIB: = 9.05), perceived the infant as KMC mothers were more normal (KMC x¯ = 1.09, CG more sensitive, x¯ = 3.32), p < .001. Medical risk mother–infant was a sig.factor, p < .05 interactions more optimal None At 3 & 6 months: KMC mothers & fathers were more sensitive (KMC mothers x¯ = 4.14, KMC fathers x¯ = 4.19; CG mothers x¯ = 3.78, CG fathers x¯ = 3.76) & less intrusive during interaction (KMC mothers x¯ = 2.02, KMC fathers x¯ = 2.02; CG mothers x¯ = 2.53, CG fathers x¯ = 2.74) & higher dyadic reciprocity (KMC mothers x¯ = 3.71, KMC fathers x¯ = 3.56; CG mothers x¯ = 3.24, CG fathers x¯ = 3.06). KMC infants: less negative emotions (KMC x¯ = 1.38, 1.27; CG x¯ = 1.51, 1.56) KMC families: more sensitivity & less intrusiveness (¯x = 3.71, 1.61) than CG (¯x = 3.44, 2.09), p < .01 KMC had larger impact on first time mothers KMC & music mothers: less stressed None (¯x not reported, p < .001) Significant effect of time (p < .01): KMC anxiety scores increasingly improved during the 3 days, CG scores remained stable (¯x not reported) KMC infants: more quiet sleep (Day 1 x¯ = 3.87, Day 2 x¯ = 4.13, Day 3 x¯ = 3.06) than CG (Day 1 x¯ = 2.20, day 2 x¯ = 1.80, Day 3 x¯ = 2.13), p < .001 and KMC less cry (Day 1 x¯ = 1.06, Day 2 x¯ = 0.40, Day 3 x¯ = 0.40) than CG (Day 1 x¯ = 0.73, Day 2 x¯ = 1.53, Day 3 x¯ = 0.82), p < .005 (Continued)


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TABLE 1. Continued Study/Design/ Country

Participants

Measures


Main Findings

Follow-Up

At 4 months using EPDS (¯x At discharge using: Miles et al., 2006 BW (g): KMC = 1,086; EPDS (Cox, Holdey, & KMC group: 20-min = KMC 6.57, CG 6.00); Sagovsky, 1987), EPDS (¯x = KMC 7.69, CG 9.26); skin-to-skin contact OCT CG = 1,133 STAI (¯x = KMC 31.49, STAI (Spielberger, STAI (¯x = KMC 34.09, CG 35.26); daily/4 weeks England GA (weeks): >32 CG 30.79) Gorsuch, Lushene, PSS (¯x = KMC 2.85, 3.35, 3.32; CG CG: similar support as Maternal ed. (years): At 12 months, using GHQ-28 Vagg & Jacobs, given to the KMC group 2.54, 3.53, 3.40); KMC = 12.8, CG = (¯x = KMC 4.63, 3.50, 1983), PSS (Miles, (no further information) MABS (¯x = 14.29, CG 15.00), n.s. 12.7 Maternal age 6.33, 0.40; CG 6.65, 4.59, No method of recording (years): KMC = 30, CG Funk, & Carlson, 6.29, 0.82); PSI (¯x = KMC 1983), PSI (Abidin, amount of parent–infant = 30.3 24.48, CG 25.23); 1983), MABS skin-to-skin contact n = 78 dyads (mothers & Parent–Infant Attachment (Wolke & St. infants) Questionnaire (¯x = KMC James-Roberts I, 1987), Parent – Infant 21.51, CG 21.85), n.s. Attachment Questionnaire (Condon & Corkindale, 1998), Video recordings of mother–infant interaction (unknown coding system), GHQ-28 (Goldberg, 1978) KMC mothers: less stressed (¯x = KMC None KMC group: 2-hr BW (g): KMC = 1,179; PSI Short Form Tallandini & (Abidin, 1990); 51.12, CG 44.50, p = .000), better at skin-to-skin contact Scalembra, 2006 CG = 1459 Video recordings, fostering social & cognitive growth daily/24 days GA (weeks): KMC = OCT coded using NCAFS CG infants: cared for by (¯x = KMC 10.85, CG 9.03, p = .025) 30.16, CG = 31.57 Italy (Barnard, 1975), KMC infants: more responsive (¯x = staff in incubators; Maternal ed.: KMC: 17 KMC 3.10, CG 2.00, p = .001) & mothers were mothers primary school, which assesses sensitivity to cues, better at expressing their needs (¯x = encouraged to visit, 2 mothers university, response to infant hold, & breastfeed their KMC 8.35, CG 6.58, p = .001) CG: 20 mothers distress, babies primary, 1 university socioemotional CG mothers participated Maternal age (years): growth fostering, in a discussion group KMC 30.42, CG 33.10 cognitive growth No method of recording n = 40 dyads fostering, clarity of amount of parent–infant cues, responsiveness skin-to-skin contact of child to caregiver KMC mothers: bigger difference in None De Macedo et al., BW (g): KMC = 1,387; VAMS (Guimaraes, KMC group: unclear calmness (KMC p = .002, CG p = Incubator Group (IG) = 1999) 2007 duration of skin-to-skin .163), strength (KMC p = .001, CG 1,934; Term Group OCT contact p = .167) clear headedness (KMC (TG) = 3,162 Brazil CGs: no information p = .004, CG p = .288) coordination reported GA (weeks): KMC = (KMC p = .001, CG p = .020) No method of recording 31.63, IG = 33.62, TG amount of parent–infant energy (KMC p = .019, CG p = = 38.7 .128), contentment (KMC p = .016, skin-to-skin contact Maternal ed.: unknown CG p = .131), tranquility (KMC p = Maternal age (years): .002, CG p = .218), KMC = 24.23, IG = quick-wittedness (KMC p = .009, 22.56, TG = 24.36 CG p = .712), relaxation (KMC p = n = 90 dyads .001, CG p = .216), attentiveness (KMC p = .001, CG p = .638), proficiency (KMC p = .003, CG p = .541), happiness (KMC p = .001, CG p = .166), amicability (KMC p = .005, CG p = .772), after interaction with baby through KMC compared to CG (Continued)



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Participants

Measures

Gathwala et al., 2008 RCT India

BW (g): KMC = 1,690; CG = 1,690 GA (weeks): KMC = 35.48, CG = 35.04 Maternal ed.: KMC: 22 mothers college, 18 middle school, 7 primary school, 3 illiterate, CG: 19 mothers college, 17 middle school, 10 primary school, 4 illiterate Maternal age: unknown n = 100 dyads

Ahn et al., 2010 OCT South Korea

BW (g): KMC = 1,486; MAI (developed by Muller, 1994 and CG = 1,572 modified by Ahn & GA (weeks): KMC = Lee, 2004), EPDS 32.10, CG = 31.9 (Cox et al., 1987) Maternal ed.: KMC: 5 mothers high school, 5 college/higher, CG: 3 mothers high school, 7 college/higher Maternal age: KMC: 30.1, CGL 31.3 n = 20 dyads (mothers & infants) BW (g): KMC = 2,257; Video recordings of mother–infant CG = 2,211 interaction, coded GA (weeks): KMC = using NCAFS 34.40, CG = 34.60 (Barnard, 1975) CRIB score: unknown Maternal ed.: unknown Maternal age: KMC = 25, CG = 24.4 n = 100 dyads

Chiu et al., 2009 RCT United States

Structured maternal interview to assess attachment (unclear whether standard assessment or developed by investigators)


Main Findings

Follow-Up

KMC group: 6-hr skin-to-skin Structured maternal interview No further follow-up at 3 months: contact daily/3 months CG: standard care in warmer KMC mothers were more involved in baby’s care (¯x = or incubator (no further information); mothers could KMC 2.00, CG 1.90, p < .05), picked the baby up more visit, feed, & touch their often (¯x = KMC 2.82, CG babies 2.06, p < .05), slept with No method of recording baby in their bed (¯x = KMC amount of parent–infant 1.54, CG 1.12, p < .05), skin-to-skin contact spent more time with baby (¯x = KMC 2.64, CG 2.06, p < .05), gained more pleasure from interaction with baby (¯x = KMC 2.84, CG 2.06, p < .05), did not go out without baby (¯x = KMC 2.66, CG 1.94, p < .05), thinking of the baby more (¯x = KMC 1.70, CG 1.02, p < .05) None KMC group higher scores on KMC group: 3 weeks of attachment (¯x = KMC 89.90, skin-to-skin contact, CG 78.20, p = .003) unclear daily amount Mothers in both groups had no CG: similar treatment to signs of depression KMC group, apart from posttreatment (¯x = KMC skin-to-skin contact (no 7.20, CG 6.30, n.s.) further information) No method of recording amount of parent–infant skin-to-skin contact

KMC group: various amounts Similar scores between groups Follow-up at 6, 12, & 18 (n.s.), no x¯ reported months CG more of skin-to-skin contact with parent & routine care by responsive to mothers at 6 staff months (¯x = KMC 8.4, CG CG: routine care by staff in 10.00, p = .001), but not at incubators, warmer beds, or 12 & 18 months (¯x = KMC bassinettes; holding in 9.00, 8.70, CG 9.60, 9.40 blankets respectively, n.s.) No method of recording Similar scores for all amount of parent–infant remaining variables at 6, skin-to-skin contact 12, & 18 months: sensitivity to cues (¯x = KMC 8.90, 8.90, 8.60, CG 8.50, 8.30, 8.20, n.s.) Response to distress: (¯x = KMC 10.00, 9.40, 9.40, CG 9.60, 9.30, 9.20, n.s.) Socioemotional growth fostering: (¯x = KMC 8.10, 8.30, 8.30, CG 8.10, 8.00, 8.60, n.s.) Cognitive fostering: (¯x = KMC 11.4, 11.90, 12.50, CG 11.10, 11.50, 12.40, n.s. Clarity of cues: (¯x = KMC 8.30, 9.00, 9.10, CG 8.70, 9.20, 9.30, n.s. (Continued)


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Participants

Measures

Neu & Robinson, BW (g): KMC = 1,999; Baseline depression & anxiety measured by Traditional Holding 2010 center for (TH) = 1,880; CG = RCT Epidemiologic 1,980 United States Studies-Depression GA (weeks): KMC = 33.14, TH = 33.42, CG Scale (CES-D; Radloff, 1977) & STAI = 33.42 (Spielberger, Gorsuch, Maternal ed.: unknown Luchane, Vagg, & Maternal age: KMC = 25.79, TH = 25.88, CG Jacobs, 1989); Still-Face Paradigm = 26.63 (Tronick, Als, n = 79 dyads (mothers & Adamson, Wise, & infants) Brazelton, 1978), scored using the Fogel Scoring System for Still-Face Observation (Fogel, 1994) and the IRSS (Weinberg & Tronick, 1996) Behaviors were coded using the Observer 5.0 software


Main Findings

Follow-Up

Measurement at 6 months of KMC group: 1-hr skin-to-skin Measures at 6 months: infant age, no futher KMC group: more symmetrical contact daily/8 weeks follow-up coregulation than TH group CG1: 1-hr daily blanket (¯x = KMC 35.73, TH 19.35, holding /8 weeks p = .04) CG2: holding of choice KMC group spent more time neither displaying positive behaviors KMC nor blanket holding during reunion with mother was encouraged. Most compared to TH & CG (¯x = mothers preferred blanket KMC 28.50, TH 9.60, CG holding. Mothers were 21.8, p = .019). No asked to record the amount differences on face vitality of skin-to-skin contact in a between groups (p = .345) diary

Note. RCT = Randomized Controlled Trial; KMC = Kangaroo Maternal Care; OCT = Other Controlled Trial; BW = Birth Weight; CG = Control Group; GA = gestational age; CRIB = medical risk score; Maternal ed. = maternal education; x¯ = mean; ES = effect size; AoB = Age of Baby; NCAFS = Nursing Child Assessment Feeding Scale; PSS-NICU = Parental Stressor Scale-NICU; PES = Parental Expectations Survey; MNCS = Mother–Newborn Coding System; CIB = Coding Interactive Behaviour; BDI = Beck Depression Inventory; NPI = Neonate Parental Inventory; ICQ = Infant Characteristics Questionnaire; HOME = Home Observation for the Measurement of the Environment; PCSC = Parental Competence & Satisfaction Scale; STAI = State-Trait Anxiety Inventory; EPDS = Edinburgh Postnatal Depression Scale; MABS = Mother & Baby Scale; GHQ-28 = General Health Questionnaire-28; VAMS = Brazilian Version of the Visual Analogue Mood Scale; MAI = Maternal Attachment Inventory; CES-D = Epidemiologic Studies-Depression Scale; STAI = State-Trait Anxiety Inventory; IRSS = Infant Regulatory Scoring System.

First, there is a possibility of performance bias, as the care that was provided to the two groups (KMC and control) was not always comparable (Higgins & Altman, 2008). On some occasions, there were differences (other than the KMC intervention) in the nursing care between groups. Specifically, in the study of Tallandini and Scalembra (2006), the researchers introduced a discussion group as a means of additional support only for mothers in the control group. Discussions around stress may have led to an increase of participants’ anxiety. There is some evidence that emotional contagion may exist in depression, which also might be true for stress (Gump & Kulik, 1997; Joiner, 1994). However, it is difficult to retrospectively establish the effects of this discussion group. In the study by Tessier et al. (1998), the amount of skin-to-skin contact varied substantially within the KMC group, and this variation was not accounted for in the analysis. The variation in the amount and patterns of KMC within experimental groups can be important factors, which can explain differences in outcome variables in studies that explore KMC outcomes in caregiver–infant dyads. On other occasions, there is a lack of details on the care that groups received (Ahn et al., 2010; De Macedo et al., 2007; Feldman et al., 2002; Lai et al., 2006; Miles et al., 2006; Roberts et al., 2000; Whitelaw et al., 1988), so performance bias cannot be ruled out. This appears to be a common issue in studies examining the effec-

tiveness of KMC. In some studies, the exact amount of KMC was not recorded or documented (Ahn et al., 2010; De Macedo et al., 2007; Miles et al., 2006; Tallandini & Scalembra, 2006; Tessier et al., 1998) whereas there is no information about the exact care that control groups received in other studies (Feldman et al., 2002; Lai et al., 2006; Miles et al., 2006; Roberts et al., 2000). The possibility of performance bias in the studies that detected significant differences makes it difficult to determine whether the differences were a result of KMC or of other, uncontrolled-for factors (Higgins & Altman, 2008). Correspondingly, the variation in care between groups may have masked group differences, leading to a Type II error in the studies that did not detect significant differences between groups (Keppel & Wickens, 2004). Furthermore, the lack of information on the exact amount of KMC that was performed by caregivers makes it difficult to draw conclusions on the amount of KMC that is required for the intervention to be effective. The absence of this information within the papers also makes it impossible to compare the findings of these studies with those of others. Finally, it is possible that important clinical information is missed, as the lack of description of the care that groups received in addition to KMC (e.g., potential additional support or practices specific to the care units) does not allow readers to determine which care characteristics might be most beneficial



for low birth weight, preterm infants and their caregivers. This issue also is relevant to studies that did not detect significant differences between groups. It would be useful to define the exact care that control groups received in these studies to understand which factors led to positive outcomes for both groups. These issues should be an avenue for future research. Detection bias also is a possibility in six studies. In the studies by Tessier et al. (1998) and Tallandini and Scalembra (2006), assessors were either not independent to the research group or blinded to group allocation during the assessments (Higgins & Altman, 2008). Moreover, in five studies (Ahn et al., 2010; De Macedo et al., 2007; Lai et al., 2006; Roberts et al., 2000; Whitelaw et al., 1988), there is not enough information to confirm that assessors were blind to group allocation, and therefore bias cannot be ruled out (Higgins & Altman, 2008). Furthermore, there is a possibility of selection bias (Higgins & Altman, 2008) in the study of Tessier et al. (1998). It is mentioned that the two groups (KMC and control) differed significantly in birth weight and gestational age, but only birth weight was controlled as a covariate in the analysis. Apart from the three types of bias discussed earlier, there are some additional methodological issues that need to be taken into account. First, the study by Lai et al. (2006) was not adequately controlled. Researchers in this study aimed to examine the effects of KMC combined with music, as compared to conventional care. They included one group who received KMC with music and one control group who received routine care. The effects of KMC in conjunction with music would have been investigated more thoroughly if another control group, receiving KMC only, was included. The absence of an additional control group makes it impossible to differentiate the effects of KMC from the effects of music. Second, in the Whitelaw et al. (1988) study, it is not clear whether the questionnaire that was used was standardized, which makes it difficult to evaluate the validity of the measurement. KMC and Parent–Preterm Infant Interaction Patterns

Researchers in nine studies investigated the effects of KMC on parent–preterm infant interaction patterns. Researchers in seven of those studies detected significant improvements in the KMC groups, as compared to control groups (Ahn et al., 2010; Feldman et al., 2002; Feldman et al., 2003; Gathwala, Singh, & Balhara, 2008; Neu & Robinson, 2010; Tallandini & Scalembra, 2006; Tessier et al., 1998), while in two studies they did not (Chiu & Anderson, 2009; Miles et al., 2006). Specifically, Ahn et al. (2010) found that mothers in the KMC group demonstrated stronger attachment to their babies than did mothers in the control group. Feldman et al. (2002) found that mothers in the KMC group exhibited more positive interactions, as demonstrated by the observations that they were looking at and touching their infants more, they showed more positive affect, and they were more adaptive to the infants’ cues. Similarly, Feldman et al. (2003) reported that mothers and fathers in the KMC group were more sensitive and less intrusive during interaction with their

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infants and exhibited higher dyadic reciprocity. However, birth order played a significant role: KMC had a greater positive effect on first-time mothers, as compared to mothers who had given birth before. Neu and Robinson (2010) compared interaction patterns between mothers and their infants in KMC, traditional (blanket) holding, and control groups. They found that dyads in the KMC group showed higher joint attention during their interactions, as compared to the traditional holding group. Comparison between the KMC and the control group showed a similar trend, but did not reach significance levels. In a similar vein, Tallandini and Scalembra (2006) found that mothers who performed KMC were more able to facilitate the infants’ social and cognitive growth through their interactions, as compared to mothers in the control group. Follow-up measurements at 41 weeks and 3 and 6 months showed that some of the improvements were still apparent. At 41 weeks’ gestational age, Tessier et al. (1998) reported that mothers in the KMC group were still more sensitive toward their infants, as compared to mothers in the control group, but the increased sensitivity appeared to be related to the infant’s health. Specifically, mothers tended to be more sensitive toward their infants when they had spent more time in the NICU. At 3 months, Gathwala et al. (2008) reported that mothers in the KMC group picked up their babies more often, slept with them in their bed, were thinking of their babies more frequently, and did not go out without them. They also were more involved in their infant’s care and gained more pleasure from interactions with them. Moreover, Feldman et al. (2003) found that both parents in the KMC group created a more sensitive and stimulating home environment through their interactions with their children and with each other. At 6 months, it also was found that mothers in the KMC groups had maintained their sensitivity and positive interactions with their infants (Feldman et al., 2002; Feldman et al., 2003). Positive effects were observed in some of the infants who received KMC. Some infants in the KMC groups showed less negative emotions during play (Feldman et al., 2003) and more positive behaviors during reunion with their mother (Neu & Robinson, 2010). They also were better at expressing their needs and more responsive to their mothers (Tallandini & Scalembra, 2006), as compared to infants who received routine care. Conversely, researchers in two studies did not detect a significant difference in mother–infant interaction patterns between KMC and control groups (Chiu & Anderson, 2009; Miles et al., 2006). Interaction patterns were found to be similar between KMC and control groups at 4, 6, 12, and 18 months. Moreover, in the study by Chiu and Anderson (2009), infants in the control group were more responsive to their mothers than were the infants in the KMC group at 6 months of age, but this difference was no longer apparent by 12 and 18 months of age. Methodological considerations. A number of methodological issues in the studies just presented need to be highlighted. Due to the fact that the main methodological issues of the studies by Ahn et al. (2010), Feldman et al. (2002), Miles et al. (2006), Tallandini and


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Scalembra (2006), and Tessier et al. (1998) were presented in the previous section, only the methodological flaws of the remaining studies (Chiu & Anderson, 2009; Feldman et al., 2003; Gathwala et al., 2008; Neu & Robinson, 2010) will be presented at this point to avoid repetition. First, the possibility of selection bias (Higgins & Altman, 2008) is present in two of these studies. In the study by Gathwala et al. (2008), there is not adequate information on whether maternal baseline characteristics were statistically compared. Given the lack of information on the similarity of maternal characteristics, the possibility of selection bias cannot be ruled out. Conversely, in the study by Chiu and Anderson (2009), participants were recruited from two different hospitals, with different levels of medical risk. According to the authors, this might have increased the differences between the two groups, leading to a greater difficulty in detecting an effect of the intervention (Chiu & Anderson, 2009). Attrition bias also is an issue in this study, as participants from the control group were the ones who were mostly lost at follow-up (Chiu & Anderson, 2009). Attrition issues also were present in the study by Neu and Robinson (2010). Moreover, performance bias may have been introduced in four studies. In the study by Feldman et al. (2003), a specialist nurse was involved only in the care of the KMC group while in the study by Gathwala et al. (2009), there is a lack of details on the care that the two groups received, so performance bias cannot be ruled out. In addition, in the studies by Gathwala et al. (2008) and Neu and Robinson (2010), the amount of KMC was not recorded or documented, so it is unclear whether all participants adhered to the study protocol. Finally, in the study by Chiu and Anderson (2009), the amount of skin-to-skin contact varied substantially within the KMC group, with two infants not receiving any skin-toskin contact. These infants’ scores were entered in the analysis, as the study adopted an intention-to-treat design; however, this could have masked possible group differences, leading to a Type II error (Keppel & Wickens, 2004). The issue concerning differences in exposure to KMC (discussed earlier) also is relevant here because the model of application that was used was different across studies. The context in which studies were conducted varied in that some were conducted in developing countries while others were in Western, high-tech NICU. Consequently, researchers in some studies used continuous KMC while others adopted the intermittent application model. For example, in the studies by Tessier et al. (1998) and Gathwala et al. (2008), infants received KMC for 24 and 6 hr daily, respectively, whereas in the studies by Miles et al. (2006) and Tallandini and Scalembra (2006), which were conducted in Western countries, the duration of KMC was much shorter. Similarly, comparison infants in the studies by De Macedo et al. (2007) and Gathwala et al. (2008) were placed in incubators, with fewer opportunities for physical proximity with their caregivers and holding. This is in contrast with some other studies where comparison infants received traditional holding (e.g., Neu & Robinson, 2010; Roberts et al., 2000). Although both the continuous and intermittent applications of KMC are used widely all over the world, the difference in exposure to

the intervention should be considered as an important factor that can explain group differences. In addition, the possibility of detection bias was present in the study by Gathwala et al. (2008), where assessors were not unaware of the care that groups received during the assessments (Higgins & Altman, 2008). Furthermore, the study by Feldman et al. (2003) used numerous statistical analyses of variance, without stating whether Bonferroni corrections were applied to post hoc comparisons. There is, therefore, a possibility that there was increased chance of Type I error (Keppel & Wickens, 2004) or that the differences observed between KMC and control groups could be explained by other group factors. In addition, researchers in three studies (Chiu & Anderson, 2009; Gathwala et al., 2008; Miles et al., 2006) did not report important statistical values such as t scores, degrees of freedom, and confidence intervals. This makes it difficult to evaluate the accuracy of their statistical analyses and highlights the need to interpret their findings with caution. Moreover, there is an additional factor to take into account when interpreting the findings of studies on interactions between parents and their preterm, low birth weight infants. In seven of the nine studies (Chiu & Anderson, 2009; Feldman et al., 2002; Feldman et al., 2003; Miles et al., 2006; Neu & Robinson, 2010; Tallandini & Scalembra, 2006; Tessier et al., 1998), interactions were assessed through video recordings and were subsequently coded by observers. However, in these studies, various coding instruments were used. Except for Chiu and Anderson (2009), Tallandini and Scalembra (2006), and Tessier et al. (2010), who utilized the Nursing Child Assessment Feeding Scale (Barnard, 1975), the remaining researchers used different tools (see Table 1), so direct comparison of their findings is difficult. Furthermore, Miles et al. (2006) did not clarify which coding instrument they used, which makes it impossible to evaluate its efficacy and validity. Note that there are some inherent issues in the method of observation, such as the effect that the act of observation can have on the participant (Stanton, Baber, & Young, 2005). It is possible that the interactions between parents and their infants were influenced by the fact that they were recorded, thus skewing the findings of the studies, as the participants may have responded with a social desirability bias (i.e., doing what they anticipated the researchers expected them to do). However, given that researchers in seven of nine studies used video to record all participants’ interactions, it is likely that this effect would have been minimal. In addition, as has been discussed throughout this review, there were issues with some of the psychometric measures used in some studies (e.g., Gathwala et al., 2008; Lai et al., 2006), which means that readers need to be cautious in their interpretation of these studies’ findings. Summary. The main findings of the studies that have examined the effects of KMC on parent–preterm infant interaction patterns and parental mood have been presented, and their methodological soundness has been evaluated. The positive outcomes, as reported in seven of the studies (Ahn et al., 2010; Feldman et al., 2002;



Feldman et al., 2003; Gathwala et al., 2008; Neu & Robinson, 2010; Tallandini & Scalembra, 2006; Tessier et al., 1998), included more positive interactions between parents (mostly mothers) and their preterm infants, more touch and positive affect, better adaptation to the infant’s cues, increased sensitivity, and less restrictive parenting. Benefits were still present throughout the age of 6 months (Feldman et al., 2002; Feldman et al., 2003; Neu & Robinson, 2010). Regarding maternal emotional well-being, improvements included less stress and depression as well as an increased sense of competence (De Macedo et al., 2007; Feldman et al., 2002; Lai et al., 2006; Tallandini & Scalembra, 2006; Tessier et al., 1998). In contrast, four studies did not detect any differences between groups (Ahn et al., 2010; Miles et al., 2006; Roberts et al., 2000; Whitelaw et al., 1988). Next, the findings of the papers described in the previous two sections will be discussed, and conclusions will be drawn regarding the effects of KMC on the areas examined.

DISCUSSION

The aim of this systematic review was to synthesize and evaluate the available data from studies on KMC to reach some conclusions about the efficacy of this intervention on the mood of mothers with preterm babies and the interaction patterns between parents and their preterm infants. Taken together, the findings of these studies were inconclusive. Some studies found a significant positive effect of KMC for both areas while other studies reported that groups (KMC and control) exhibited similar behaviors. Surprisingly, even studies which used the same measures (e.g., the Parent Stress Index; Barnard, 1975) did not manage to find similar results. Although this might initially appear incomprehensible, there are some possible explanations such as the presence of methodological flaws in the studies (Lijmer, Bossuyt, & Heisterkamp, 2002). An important factor could be the differences in exposure to KMC in mothers within experimental groups, which may have influenced the overall outcomes. It also could be the case that certain types of bias either masked or inflated group differences in the studies described, leading to mixed results. This possibility cannot be dismissed despite the fact that researchers used several means to ensure quality. For example, most researchers had given consideration to decreasing selection bias, either by randomly allocating participants to groups (Chiu & Anderson, 2009; Gathwala et al., 2008; Lai et al., 2006; Neu & Robinson, 2010; Roberts et al., 2000; Tessier et al., 1998; Whitelaw et al., 1988) or—whenever randomization was impossible—by matching groups for participant characteristics such as gender, age, birth weight, medical risk, parental age, education, parity, and employment status (Feldman et al., 2002; Feldman et al., 2003). Some researchers also stated that they had tried to equate the nursing care that groups received (Chiu & Anderson, 2009; Feldman et al., 2003; Neu & Robinson, 2010; Tessier et al., 1998; Whitelaw et al., 1988) to reduce performance bias while others reported that assessments were carried out by assessors blind to group allocation (Chiu & Anderson, 2009; Feldman et al., 2002; Feldman et al., 2003).

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Nevertheless, it is possible that the nature of the topic makes it rather difficult to avoid certain types of bias. For example, as discussed earlier, randomization is not always without problems in those studies whereas participant allocation concealment is impossible because mothers could not possibly have been blind to their treatment. Finally, complete equation of the nursing care that individuals receive may be beyond the researchers’ control, as this is a factor often regulated by hospitals. There are, however, other factors that can be adequately controlled by researchers, such as ensuring that data collection and entry as well as coding are performed blindly. Researchers also need to measure or equate the attention and support that mothers in the KMC group receive to eliminate this potential confounded variable and reach more stable conclusions about the efficacy of KMC. For example, other components of KMC, such as lactation and breastfeeding, can be encouraged by supporting mothers to perform them as a means to enhance maternal role attainment and mood. Future research is needed to address these issues. Furthermore, studies were heterogeneous in their design, participant characteristics, measures, and amount of KMC (see Table 1). For example, there was a large variation in birth weight, gestational age, amount of KMC, parental education and income, and assessment tools. For example, some researchers used standardized, widely used assessment tools while others used idiosyncratic tools. There also was variation in the coding methods that were used to interpret recordings of the interaction between parents and their preterm babies postintervention while some researchers have not used methods to record KMC duration or patterns. Such heterogeneity can make the studies incomparable, thus hindering the generation of generalizable conclusions (Lijmer et al., 2002). The heterogeneity in study outcomes also could be explained by variations in participants’ experiences using KMC, other than the KMC procedure itself. For example, different NICU may have different policies concerning the parents’ presence and involvement in their infants’ care. When opportunities for physical proximity and involvement in the infant’s care are limited, parents may feel excluded from the early stages of their child’s life, which can have significant implications on their mood and interactions with their infant, as discussed previously (Stern, 1977; Tallandini & Scalembra, 2006). Similarly, the level of support provided to parents by healthcare staff as well as practical facilities such as room structure and equipment where KMC is performed can be variable among hospitals and can influence parents’ experiences of KMC and subsequent outcomes (Blomqvist & Nyqvist, 2010). Other factors such as participants’ socioeconomic or educational status, which also were variable across studies, may have contributed to the inconsistent outcomes. However, the heterogeneity across studies may reflect a real variation in the effects of KMC. It can be the case that KMC has different effects on different groups of preterm, low birthweight babies under different conditions. Two of these conditions can be birth weight itself and medical risk. Part of the literature on preterm infants has indicated that very low birth weight, in


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conjunction with increased medical risk, can increase parental stress and worry around the baby’s survival and health (Brisch et al., 2003; Singer et al., 2003). In addition, very low birth weight can pose difficulties on early interaction patterns between parents and their preterm infants because infants’ temperament can be perceived as difficult (Spielman & Taubman-Ben-Ari, 2009). Some studies that were included in this review have supported such an interpretation. The two studies which have included babies of the lowest birth weight (Miles et al., 2006; Whitelaw et al., 1988) did not find a significant improvement for participants in the KMC groups. It is therefore possible that parents of very low birth weight infants, who are at higher medical risk, are those who benefit less from KMC because their stress, worry, and/or depression levels are too high to be mitigated by skin-to-skin contact. Besides, higher levels of maternal depression can have an additional negative impact on parent–infant interactions (Milgrom, Ericksen, McCarthy, & Gemmill, 2006). Nevertheless, the different contributions of birth weight and medical risk need to be explored in more depth, possibly through a meta-analysis, to better understand the benefits of KMC on different preterm groups. Another factor that might have contributed to the inconclusive findings of the studies, in relation to parent–preterm infant interaction, is the assessment method that was used. As discussed earlier, the majority of studies used coded observations to assess parent–infant interaction patterns. However, the process of observing and recording human behavior can be complex, and several factors can interfere with the behavior of the person who is observed. For example, it has been suggested that the actual presence of an observer can alter human behaviour (Stanton et al., 2005) while the level of involvement, the expectations of the researcher, and the relationship between observer and participant can have a significant effect on participant performance (Schwartz & Schwartz, 1955; Stanton et al., 2005). It is therefore possible that the effects of observation and recording on the interaction between parents and infants played a separate role in the results of these studies and could explain some of the variation within their findings. It also is important to consider the possibility that research on human behavior is influenced by cultural or personal norms. It is possible that the sociocultural context in which the results of the studies were interpreted had a unique impact on the interpretation of the phenomena that were observed. An example of this could be the study by Gathwala et al. (2008), in which mothers slept with their babies in their bed, were thinking of their babies more frequently, and did not go out without them, which was interpreted as an indication of stronger and better attachment. An alternative interpretation could be that these findings indicate greater maternal anxiety and overprotection, which could be viewed as risk factors for insecure attachment (Kaitz & Maytal, 2005). However, this interpretation may merely reflect the first author’s cultural or personal norms, and it highlights the need for awareness of these factors when making judgments on study findings, especially when human behavior is concerned.

Despite the presence of the aforementioned issues, the positive effects of KMC that were reported by the majority of studies have a clinical value and need to be taken into account. Nine studies found that KMC contributed to the decrease of maternal stress and depression and/or to the promotion of more positive interactions between parents and their preterm infants (Ahn et al., 2010; De Macedo et al., 2007; Feldman et al., 2002; Feldman et al., 2003; Gathwala et al., 2008; Lai et al., 2006; Neu & Robinson, 2010; Tallandini & Scalembra, 2006; Tessier et al., 1998). The first, and perhaps the most plausible, explanation of these findings is that the benefits of KMC can be attributed to increased physical contact and touch. It has been shown that touch is an important component of the early mother–infant relationship because it can enhance early mother–infant interaction, and promote psychological wellbeing—for both mothers and infants (Jones & Mize, 2007). Based on this rationale, however, one would expect that any kind of increased physical contact would bring about similar positive outcomes. Surprisingly, this was not the case in Roberts et al.’s (2000) study, where both groups (KMC and conventional cuddling) exhibited comparable high stress scores. Conversely, Neu and Robinson (2010) compared KMC with traditional holding (with a blanket) and found that KMC resulted in better mother–infant interaction. This contrast in findings might be a result of methodological problems, so future research needs to further explore the effects of KMC in comparison with conventional holding and touch to come to more stable conclusions of the potential different contributions of KMC and traditional holding. Another possible explanation is that mothers in the KMC groups were less stressed, or more stress-resilient, because they were more involved in their infant’s care and they felt more in control of it (Tallandini & Scalembra, 2006; Tessier et al., 1998). It has been suggested that locus of control can regulate stress and depression. People who perceive themselves as being in control of a stressful or negative situation are more likely to experience lower levels of stress and depression, as compared to people who believe that control lies in external sources (Abouserie, 1994; Benassi, Sweeney, & Dufour, 1988; Krause & Stryker, 1984). It is possible, then, that KMC creates a greater sense of control for mothers, through actively caring for their baby, which results in stress and depression reduction or resilience. Finally, to conclude on the duration of the positive effects of KMC over time, it is important to examine the follow-up phases of the studies included in this systematic review. Although positive effects were generally found within 6 months after the intervention, studies which followed their participants for up to 18 months did not detect any significant positive effects. This may suggest that any positive effects gained by KMC can wear off over time. Alternatively, it could mean that all groups (KMC and routine care) exhibited similar positive characteristics such as positive mother–infant interactions and optimum maternal mood. In reality, the question of the long-term impact of KMC can be answered only by longitudinal studies, which have not been conducted to date.



In summary, the findings of the reviewed studies have suggested that KMC can have positive effects on maternal mood and parent–infant interaction patterns. Specifically, five of nine studies have indicated that KMC helped to ameliorate maternal anxiety or depression (De Macedo et al., 2007; Feldman et al., 2002; Lai et al., 2006; Tallandini & Scalembra, 2006; Tessier et al., 1998). In addition, seven of nine studies (Ahn et al., 2010; Feldman et al., 2002; Feldman et al., 2003; Gathwala et al., 2008; Neu & Robinson, 2010; Tallandini & Scalembra, 2006; Tessier et al., 1998) found that KMC helped to improve parent–infant interaction patterns. Despite the methodological limitations that were described earlier, these findings have indicated that KMC can help to improve the adverse psychological effects that a preterm birth can involve, such as parental anxiety and depression. It also is possible that KMC can facilitate parent–preterm infant bonding and early attachment because it enables parents to spend more time with their infants, as opposed to traditional care in incubators, thus diminishing the adverse effects of early separation. Some questions, however, need to be addressed in future research, as discussed next. LIMITATIONS AND FUTURE DIRECTIONS

This systematic review focused on randomized and other controlled clinical trials because these are the most appropriate designs to evaluate the efficacy of interventions (Greenhalgh, 2006). Researchers in the studies included in this review have used quantifiable measures to assess parent–preterm infant interaction patterns. Nevertheless, it is possible that the complex processes of human interaction cannot be captured in standardized measures (Chiu & Anderson, 2009). Qualitative methodologies may be more relevant when examining human behavior because they are more applicable to real-life situations and allow for a more thorough exploration of individual experiences as well as of the meaning and purposes of behaviors (Willig, 2001). For example, several qualitative studies have shown that mothers who choose to perform KMC feel closer to their infants, have a greater sense of mastery, and overall better feelings toward their child (e.g., Johnson, 2007). Although qualitative studies were not included in this systematic review, as it was beyond its scope, it may be that future reviews should focus on qualitative research and create a meta-synthesis of their findings. Future reviews also should include research focusing on mothers who prefer conventional holding, as a comparison of themes between kangaroo and conventional holding may aid our understanding on the topic. Future Research

The studies that were presented in this review were not homogeneous, so future reviews should explore the heterogeneity between studies in greater depth (Lijmer et al., 2002) to understand the impact of KMC. Future research also needs to be conducted with the aim to examine the effects of KMC in more homogeneous and comparable participant groups. In addition, future studies need

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to be more explicit regarding the exact care that groups receive and to employ methods for valid and reliable record-keeping of skin-to-skin time. Similarly, other components that were discussed previously, such as different NICU policies and staff attitudes that affect parent–infant interactions and parents’ involvement and confidence in their parental role, need to be further explored. In line with recommendations for KMC, the level of support that mothers receive in relation to lactation and breastfeeding as well as timely discharge from the hospital and appropriate follow-up (Cattaneo et al., 1998; Nyqvist et al., 2010) need to be further studied to enable a greater understanding of the factors that can contribute to better treatment for preterm infants and their parents. Finally, it also is important to employ more appropriate methodologies, such as universal observation coding systems, to make the findings comparable and generalizable, or to examine the effects of KMC in natural contexts that are representative of families’ everyday life. CONCLUSIONS

In summary, we have found evidence for the efficacy of KMC at promoting more positive parent–preterm infant interaction patterns and maternal mood. However, considering the presence of methodological limitations and the fact that the positive effects of KMC on the areas examined were not demonstrated by all the studies included in this review, there is a need for future research with robust methodologies if stable and safe conclusions on the efficacy of KMC on these specific areas are to be reached. Given the importance of parent–infant interaction and maternal mood for the preterm infants’ later development, the effects of KMC on these areas are definitely worth exploring in more depth.

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