Front. Med. Frontiers in Medicine Front. Med. 2296-858X Frontiers Media S.A. 10.3389/fmed.2025.1736973 Systematic Review Efficacy and safety of Kangaroo mother care vs. conventional care during hospitalization for preterm and/or low birth weight infants: a meta-analysis with trial sequential analysis of randomized controlled trials Li Li † Writing – original draft Formal analysis Investigation Data curation Software Conceptualization Tan Qiong † Visualization Methodology Formal analysis Investigation Writing – original draft Li Hongyu * Writing – review & editing Conceptualization Validation Investigation Supervision Department of Gynecology and Obstetrics, The First Affiliated Hospital of Army Medical University, Chongqing, China Correspondence: Hongyu Li, Leerain1971@Tmmu.edu.cn

These authors have contributed equally to this work and share first authorship

 14 01 2026 2025 12 1736973 31 10 2025 27 11 2025 05 12 2025 Copyright © 2026 Li, Tan and Li. 2026 Li, Tan and Li https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Background

Kangaroo mother care (KMC) plays a significant role in reducing mortality among preterm or low birth weight (LBW) infants. However, comprehensive evidence regarding various clinical outcomes during hospitalization for neonates receiving KMC remains limited. This meta-analysis focuses on hospital-based KMC and aims to evaluate its efficacy and safety for neonates during their hospital stay.

 Methods

A systematic search of the literature was undertaken across major databases, including PubMed, Web of Science, Embase, and the Cochrane Library, to identify randomized controlled trials (RCTs) published up to July 9, 2025. Binary outcomes were analyzed using risk ratio (RR), while continuous data were assessed using standardized mean difference (SMD) or mean difference (MD), each reported with corresponding 95% confidence intervals (CIs). To evaluate heterogeneity among studies, the Cochrane Q test, I2 statistic, and 95% prediction intervals (PIs) were utilized. Additionally, trial sequential analysis (TSA) was applied to mitigate potential type I and type II errors in the meta-analysis.

 Results

This meta-analysis synthesized data from 31 RCTs, encompassing 8561 preterm and/or LBW infants. The findings of this meta-analysis indicated that compared with conventional care, KMC significantly reduced in-hospital mortality [RR (95% CI) = 0.791 (0.696–0.899), 95% PI: 0.679–0.925] and 28-day all-cause mortality [RR (95% CI) = 0.810 (0.709–0.926), 95% PI: 0.605–1.085]. Furthermore, KMC was associated with shorter duration of hospitalization [MD (95% CI) = −0.809 (−1.601, −0.017), 95% PI: −3.219, 1.601] and notable improvements in growth parameters, including accelerated weight gain, increased length growth, and enhanced head circumference growth during the hospital stay (all p < 0.05). Regarding clinical safety, KMC was associated with lower risks of hypothermia, hyperthermia, apnea, sepsis, and necrotizing enterocolitis (all p < 0.05). Subgroup analyses further emphasized the marked clinical effectiveness and favorable safety profile of KMC, particularly in lower-middle-income countries.

 Conclusion

KMC is a clinically effective and safe intervention for the management of preterm and/or LBW neonates. Present evidence highlights its role in reducing neonatal mortality, expediting hospital discharge, fostering growth and developmental outcomes, as well as mitigating the incidence of complications. Moreover, the benefits of this intervention are particularly significant in lower-middle-income countries.

 conventional care infants Kangaroo mother care (KMC) low birth weight mortality preterm The author(s) declared that financial support was not received for this work and/or its publication. section-at-acceptance Obstetrics and Gynecology Introduction

Premature birth, defined as delivery before 37 weeks of pregnancy, and low birth weight (LBW), referring to infants weighing < 2,500 g, are significant contributors to neonatal and infant deaths (1). Globally, an estimated 13.4 million babies are delivered prematurely each year, and approximately one in four newborns are born frail and at risk, including those born preterm or small for gestational age (SGA) (2). These conditions not only represent the leading causes of mortality in children but also contribute substantially to long-term developmental and economic losses (2). The burden of preterm and low birth weight births is disproportionately high in low- and middle-income nations, where deficiencies in neonatal healthcare services exacerbate the problem (3).

Kangaroo mother care (KMC), which involves sustained skin-to-skin contact between the infant and the mother's chest alongside exclusive breastfeeding, is a highly effective intervention for reducing mortality among preterm and/or LBW neonates (4). The benefits of this approach have been well-documented, with evidence demonstrating its positive impact on key physiological parameters, including improved oxygenation, enhanced thermoregulation, stabilization of blood glucose levels, and overall homeostatic balance. Furthermore, KMC has been associated with advancements in neurodevelopmental and cognitive outcomes (5, 6). The close physical contact during KMC promotes exclusive breastfeeding and fosters a stronger maternal-infant bond (7). The implementation of KMC, however, varies widely across neonatal care practices, with its adoption being inconsistent across low-, middle-, and high-income countries. A Cochrane review found that providing KMC to stabilized LBW infants led to a 40% reduction in mortality compared to standard hospital care. This review also identified additional benefits, including lower rates of infection, improved weight gain, and increased prevalence of exclusive breastfeeding (8). Subsequent pooled analyses have reinforced these findings, demonstrating the substantial role of KMC in improving survival rates and reducing the risk of infections in preterm and/or LBW infants (9, 10).

Although systematic reviews have established the effectiveness of KMC, much of the existing evidence has been concentrated on its impact in reducing neonatal mortality and infection rates, with other dimensions of its clinical efficacy and safety remaining underexplored. Moreover, short-term outcomes observed during hospitalization may offer a more immediate and reliable measure for clinical benefits of KMC, as opposed to long-term follow-up results post-discharge, which are often influenced by a broader range of dynamic and unpredictable factors over time. Therefore, this study conducted a comprehensive analysis of randomized controlled trials (RCTs), with an emphasis on evaluating the efficacy and safety of hospital-based KMC compared with conventional neonatal care for LBW and/or preterm infants during their hospital stay. Further subgroup analyses were conducted to explore the clinical effects of KMC across countries with varying income levels. The findings aim to provide robust, evidence-based insights for policymakers and stakeholders to inform healthcare decisions and policies.

 Methods Study design

The meta-analysis was registered in the PROSPERO database under the identifier CRD420251146574. The research adhered to the principles and recommendations specified in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) (11).

 Search strategy

Two independent researchers conducted extensive literature searches across major international databases, including PubMed, Web of Science, Embase, and the Cochrane Library, to locate relevant studies published from inception through July 9, 2025. The search strategy targeted two primary domains: keywords associated with KMC (e.g., “kangaroo-mother care,” “kangaroo care,” “kangaroo mother method,” “skin to skin care,” “skin-skin care,” and “skin to skin contact”) and terms specific to infants, such as “preterm,” “premature,” “low birth weight,” “LBW,” “underweight,” and “VLBW”. The search was restricted to clinical RCTs. Detailed search methodologies were applied for each database, as outlined in Supplementary Files 1. The search was confined to studies involving human participants, with no restrictions on language. Furthermore, manual screening of reference lists from pertinent publications was performed to identify any additional eligible RCTs.

 Inclusion and exclusion criteria

To be included, studies were required to fulfill the following criteria: (1) RCTs; (2) participants were preterm and/or LBW infants; (3) the intervention involved KMC, while the comparison group received conventional care; (4) outcomes assessed included measures of efficacy, such as in-hospital mortality, duration of hospitalization, exclusive breastfeeding at discharge, and growth parameters (e.g., weight, length, or head circumference gain during hospitalization). Safety outcomes encompassed adverse events (AEs) such as hypothermia, hyperthermia, apnea, sepsis, necrotizing enterocolitis (NEC), and hypoglycemia occurring during the hospital stay. Studies were excluded based on the following criteria: (1) non-RCT designs, including observational studies or single-arm trials; (2) study populations consisting of term or normal birth weight newborns; (3) interventions involving community-based KMC or outcomes unrelated to in-hospital endpoints; (4) animal research, case reports, letters, conference abstracts, or correspondences. To ensure the inclusion of more recent and clinically relevant evidence, studies published before 2000 were excluded from this meta-analysis.

 Data extraction and quality assessment

Two reviewers independently extracted data from the included studies, utilizing a standardized data collection template. Extracted information included the name of the first author, publication year, country, study design, the caregiving interventions implemented in the intervention and control groups, sample size, birth weight, and gestational age in the intervention and control groups, stabilization status of the neonates and their use of invasive or non-invasive respiratory support. The methodological quality of the included RCTs was appraised using the modified Jadad scale (12), which evaluates critical elements such as the method of randomization, allocation concealment, blinding procedures, and documentation of participant withdrawals. Trials scoring between 0 and 3 were categorized as low quality, whereas those with scores of 4 or above were considered high quality. Discrepancies between reviewers were resolved through consensus discussions or, when necessary, by consulting a third investigator.

 Statistical analysis

Binary and continuous outcomes were synthesized using risk ratio (RR), standardized mean difference (SMD), or mean difference (MD), each accompanied by their respective 95% confidence intervals (CIs). Heterogeneity among studies was evaluated using the Cochrane Q test, I2 statistic, and 95% prediction intervals (PIs), with significant heterogeneity defined as a p-value < 0.1 or an I2 value exceeding 50% (13, 14). A fixed-effects model was applied when heterogeneity was no significant, whereas a random-effects model, employing the DerSimonian and Laird approach, was used in the presence of substantial heterogeneity (15). Subgroup analyses were performed based on study quality or national income levels, categorized according to the World Bank classification (low-, lower-middle-, upper-middle-, and high-income countries) (16). Sensitivity analyses were conducted by systematically omitting individual studies to test the robustness of the combined estimates. Publication bias was assessed through visual inspection of funnel plots and further analyzed using Begg's and Egger's tests (17, 18). All statistical analyses were carried out using R software 4.3.2 and STATA 12.0. A two-tailed p-value of < 0.05 was considered statistically significant.

 Trial sequential analysis

To mitigate the risk of type I and type II errors in the meta-analysis, trial sequential analysis (TSA) was employed (19). The analysis was performed using TSA software version 0.9.5.10 Beta, which calculated the required information size (RIS) and established sequential monitoring boundaries. When the cumulative Z-curve surpassed the RIS threshold or intersected the monitoring boundary, it indicated that the evidence was sufficient, and additional studies were unnecessary. The RIS was determined based on predefined parameters, including a two-sided significance level (α = 0.05), a statistical power of 80% (1 – β = 0.80), and an assumed 15% relative risk reduction (RRR).

 Results Study selection procedure

The study selection process is summarized in Figure 1. An initial database search identified a total of 2,826 records. After duplicate entries were eliminated, 1,711 articles remained for title and abstract screening. Of these, 1,589 were excluded as they were unrelated to the research topic, leaving 122 articles for comprehensive full-text review. Upon further assessment, 91 studies were excluded for the following reasons: 12 were not RCTs, 10 did not involve preterm or LBW infants as the study population, 41 did not report the required outcome data, and 28 had intervention or control designs that did not meet the inclusion criteria. Ultimately, 31 studies fulfilled the eligibility requirements and were included in the meta-analysis (3, 20–49).

Flow diagram of the process of study selection. RCTs, randomized controlled trials; LBW, low birth weight.

Flowchart detailing the study selection process for a meta-analysis. Initially, 2,826 records were identified through databases such as PubMed, Web of Science, Embase, and the Cochrane Library. No records were added from other sources. After removing duplicates, 1,711 records remained for screening. Of these, 1,589 were excluded based on titles and abstracts. Full-text assessment was conducted on 122 articles, excluding 91 for reasons such as not being randomized controlled trials, not involving premature or low birth weight infants, lacking outcome data, or not meeting inclusion criteria. Ultimately, 31 studies were included in the meta-analysis. Study characteristics and quality assessment

The characteristics of the studies included in this meta-analysis are summarized in Table 1. To ensure the inclusion of more recent literature, studies published before 2000 were excluded. Consequently, 31 RCTs, all published in English between 2000 and 2025, were analyzed. These trials involved a total of 4,293 preterm and/or LBW infants receiving KMC, while 4,268 infants in the control groups underwent conventional care. Based on the World Bank classification, the studies were conducted in countries spanning various income levels: low-income nations (The Gambia, Ethiopia, and Uganda), lower-middle-income nations (Nepal, Egypt, India, Philippines, Bangladesh, Kenya, Vietnam, Ghana, Nigeria, Tanzania, and Pakistan), upper-middle-income nations (China, Indonesia, Malaysia, and Turkey), and high-income nations (United States, Norway, Australia, and Sweden). Quality assessment revealed that 18 studies were rated as high-quality, while 13 were categorized as low-quality, primarily due to challenges in blinding intervention procedures and outcome evaluations. Further details regarding the quality assessment process are provided in Supplementary Files 2.

Characteristics of the included studies.

Author (year) Country Design Intervention description Control description Intervention group Control group Stabilisation status Received invasive or non-invasive respiratory support
Participants Birth weight (g) Gestational age (weeks) Participants Birth weight (g) Gestational age (weeks)
WHO Immediate KMC Study Group et al. (2021) Ghana, India, Malawi, Nigeria, and Tanzania RCT Immediate KMC Conventional care in an incubator or a radiant warmer (including KMC after stabilization) 1609 infants with a birth weight between 1,000 and 1,799 g 1500 ± 200 32.6 ± 3.0 1602 infants with a birth weight between 1,000 and 1,799 g 1500 ± 200 32.6 ± 2.8 Unstable Non-invasive
Brotherton et al. (2021) The Gambia RCT Early continuous KMC before stabilization Conventional care in an incubator or under a radiant heater (including continuous KMC after stabilization) 138 neonates with a birth weight < 2,000 g Median (IQR): 1459 (1,204–1,650) Median (IQR): 33 (31–34) 141 neonates with a birth weight < 2,000 g Median (IQR): 1,436 (1,180–1,660) Median (IQR): 32 (31–34) Unstable Non-invasive
Acharya et al. (2014) Nepal RCT KMC Conventional care (without KMC) 63 neonates with a birth weight < 2,000 g 1,385.87 ± 234.12 32.22 ± 2.4 63 neonates with a birth weight < 2,000 g 1,458.57 ± 172.66 32.54 ± 1.87 Stable None
Worku et al. (2005) Ethiopia RCT Early continuous KMC Conventional care 62 infants with a birth weight < 2,000 g Mean (Range): 1,514.8 (1,000–1,900) 32.42 (Mean) 61 infants with a birth weight < 2,000 g Mean (Range): 1471.8 (930–1,900) 31.59 (Mean) Unstable Non-invasive
Ramadan et al. (2025) Egypt RCT KMC Conventional care 120 infants with a birth weight of < 2000 g 1,450.2 ± 135.3 32.1 ± 1.5 120 infants with a birth weight of < 2,000 g 1448.3 ± 137.6 32.0 ± 1.6 Stable Non-invasive
Ali et al. (2009) India RCT KMC Conventional care (radiant warmers, cots in warm room) 58 neonates with a birth weight between 1200 and 1800 g 1607 ± 211 33.1 ± 2.3 56 neonates with a birth weight between 1,200 and 1,800 g 1615 ± 179 33.6 ± 2.29 Stable NR
de Ocampo et al. (2021) Philippines RCT KMC Conventional care 26 neonates with a birth weight ≤ 1500 g 1,166.1 ± 0.19 32.5 ± 2.76 26 neonates with a birth weight ≤ 1,500 g 1,210.0 ± 0.23 32.1 ± 2.51 Stable None
Nimbalkar et al. (2014) India RCT Immediate KMC Conventional care under radiant warmer 50 newborns weighing ≥ 1800 g 2,622.2 ± 398.69 37.8 ± 1.43 50 newborns weighing ≥ 1800 g 2,588.9 ± 443.25 37.7 ± 1.28 Stable NR
Tumukunde et al. (2024) Uganda RCT Early KMC Conventional care in an incubator or radiant heater (with KMC possible after stabilisation) 1110 neonates with a birth weight between 700 and 2000 g 1,500.0 ± 300.0 32.3 ± 2.4 1111 neonates with a birth weight between 700 and 2,000 g 1,500.0 ± 300.0 32.3 ± 2.2 Unstable Non-invasive
Gathwala et al. (2010) India RCT KMC Conventional care under a warmer or incubator (without KMC) 50 neonates with a birth weight of ≤ 1,800 g 1,690 ± 110 35.48 ± 1.20 50 neonates with a birth weight of ≤ 1,800 g 1,690 ± 120 35.04 ± 1.09 Stable NR
Hoque et al. (2017) Bangladesh RCT Intermittent KMC Conventional care under radiant warmer and incubator 40 infants weighing 1,250 to 1,800 g NR NR 40 infants weighing 1,250 to 1,800 g NR NR Stable NR
Rojas et al. (2003) USA RCT KMC Conventional care (without KMC) 33 neonates with a birth weight of ≤ 1500 g and gestation ≤ 32 weeks 906 ± 245 26.6 ± 2.3 27 neonates with a birth weight of ≤ 1,500 g and gestation ≤ 32 weeks 939 ± 230 27.2 ± 2.3 Stable Non-invasive
Ghavane et al. (2012) India RCT KMC Conventional care (incubator/ warmer) 71 infants with a birth weight < 1500 g 1,170 ± 191 30.8 ± 2.1 69 infants with a birth weight < 1,500 g 1,198 ± 194 30.7 ± 2.1 Stable None
Lumbanraja (2016) Indonesia RCT KMC Conventional care in an incubator 20 infants with a birth weight of 1,000–2,500 g 1,882 ± 293.125 NR 20 infants with a birth weight of 1,000–2,500 g 1,803 ± 217.234 NR Stable None
Hake-Brooks et al. (2008) USA RCT KMC Conventional care 36 infants with a birth weight between 1300 and 3000 g NR 32–36 30 infants with a birth weight between 1300 and 3000 g NR 32–36 Stable Non-invasive
Kristoffersen et al. (2023) Norway RCT KMC Conventional care 51 preterm infants born at gestational age 28–32 weeks with birth weight >1,000 g 1,436 ± 266 30.3 ± 1.1 57 preterm infants born at gestational age 28–32 weeks with birth weight >1,000 g 1,438 ± 257 30.3 ± 1.2 Stable None
Boo et al. (2007) Malaysia RCT KMC Conventional care 64 infants with a birth weight < 1,501 g 1,515 ± 120 NR 62 infants with a birth weight < 1,501 g 1,492 ± 128 NR Stable Non-invasive
Kumbhojkar et al. (2016) India RCT KMC Conventional care 60 neonates with a birth weight of < 2,000 g 1677.16 ± 201.26 32.43 ± 1.8 60 neonates with a birth weight of < 2,000 g 1699 ± 199.34 32.40 ± 1.94 Stable None
Chwo et al. (2002) China RCT KMC Conventional care (without KMC) 17 infants with gestation of 34–36 weeks NR 34–36 17 infants with gestation of 34–36 weeks NR 34–36 Stable None
Singh et al. (2024) India RCT KMC Conventional care under radiant warmers 40 neonates with a birth weight of 1,000–1,800 g NR NR 40 neonates with a birth weight of 1,000–1,800 g NR NR Stable None
Pratiwi et al. (2009) Indonesia RCT Early KMC Conventional care 48 newborns with a birth weight of 1,500–2,250 g 2,033.75 ± 159.34 35.63 ± 2.27 45 newborns with a birth weight of 1,500–2,250 g 1,987.78 ± 176.06 35.53 ± 2.31 Stable None
Mwendwa et al. (2012) Kenya RCT KMC Conventional care in incubators or cots 85 infants with a birth weight of 1,000–1,750 g 1,514 (Mean) 32.7 (Mean) 81 infants with a birth weight of 1,000–1,750 g 1,536 (Mean) 33.3 (Mean) Stable NR
Çaka et al. (2023) Turkey RCT KMC Conventional care 84 infants with a birth weight of 1,000–2,500 g and gestation 28–36 weeks 1,756 ± 503 32.10 ± 2.82 84 infants with a birth weight of 1,000–2,500 g and gestation 28–36 weeks 1,901 ± 557 32.78 ± 2.51 Stable None
Kadam et al. (2005) India RCT KMC Conventional care 44 neonates with a birth weight of < 1,800 g 1,467 ± 228 33.3 ± 2.1 45 neonates with a birth weight of < 1,800 g 1,461 ± 217 34 ± 1.7 Stable None
Chi Luong et al. (2016) Vietnam RCT KMC Conventional care (without KMC) 50 infants weighing between 1,500 and 2,490 g 2,060 ± 291.9 33.6 ± 1.8 50 infants weighing between 1,500 and 2,490 g 2,081 ± 259.3 33.9 ± 1.8 Unstable Non-invasive and invasive
Ramanathan et al. (2001) India RCT KMC Conventional care under warmer or in the incubator 14 infants with a birth weight < 1,500 g 1,219 ± 186.4 Median (Range): 30.4 (28.8–34.1) 14 infants with a birth weight < 1,500 g 1,270.9 ± 170.4 Median (Range): 30.9 (29.0–33.3) Stable Non-invasive
Lode-Kolz et al. (2023) Norway and Sweden RCT Immediate KMC Conventional care (including KMC after the 6 first hours) 46 neonates with gestation of 28–33 weeks Mean (Range): 1,572 (702–2,352) Mean (Range): 31.3 (28.9–32.7) 45 neonates with gestation of 28–33 weeks Mean (Range): 1,495 (555–2,440) Mean (Range): 31.1 (28.6–32.9) Unstable Non-invasive and invasive
Roberts et al. (2000) Australia RCT KMC Conventional care 16 premature or SGA infants 1,562 ± 465 31.7 ± 3.1 14 premature or SGA infants 1,481 ± 409 31.2 ± 2.4 Stable Non-invasive
Ricero-Luistro et al. (2021) Philippines RCT KMC Conventional care 35 neonates with a birth weight of 1,000–2,000 g and gestation < 36 weeks 1,559.43 ± 330.20 32.69 ± 2.60 35 neonates with a birth weight of 1,000–2,000 g and gestation < 36 weeks 1,551.29 ± 287.82 32.34 ± 2.22 Unstable Non-invasive
Suman et al. (2008) India RCT KMC Conventional care 103 neonates with a birth weight of < 2,000 g 1,683.4 ± 235 35.3 ± 2.3 103 neonates with a birth weight of < 2,000 g 1,723.6 ± 242 35.9 ± 2.1 Stable None
Manzoor et al. (2023) Pakistan RCT KMC Conventional care 50 infants with a birth weight of 1,500–2,499 g NR 33.06 ± 2.132 50 infants with a birth weight of 1,500–2,499 g NR 32.96 ± 2.03 Stable None

RCT, randomized controlled trial; KMC, kangaroo mother care; IQR, interquartile range; NR, not reported; SGA, small for gestational age.

 Overall and subgroup analysis of the efficacy outcomes In-hospital mortality and all-cause mortality at 28 days

8 studies examined the impact of KMC on in-hospital mortality among preterm and/or LBW infants. Given the absence of significant heterogeneity across the included trials, a fixed-effects model was applied for the statistical analysis (I2 = 0%, Tau2 = 0). The aggregated findings revealed a significant reduction in neonatal in-hospital mortality among infants receiving KMC compared to those who received conventional care [RR (95% CI) = 0.791 (0.696–0.899), 95% PI: 0.679–0.925] (Table 2, ). Subgroup analyses further demonstrated that the reduction in mortality was statistically significant in studies conducted in lower-middle-income countries or in trials assessed as high-quality (all p < 0.05). Conversely, studies performed in low-income settings or those rated as low-quality did not show a similar decrease in mortality rates (all p > 0.05) (Table 2, Supplementary Figure S1).

Pooled effect and subgroup analysis of the efficacy outcomes of kangaroo mother care for preterm or low birth weight infants.

Outcomes and subgroups Number of studies Meta-analysis Heterogeneity
RR/MD/SMD 95% CI p value 95% PI I2, Tau2 p value
In-hospital mortality
Overall 8 0.791 0.696–0.899 < 0.001 0.679–0.925 0%, 0 0.787
World Bank classification
Low income 3 0.845 0.697–1.024 0.086 0.551–1.281 0%, 0 0.423
Lower-middle income 5 0.752 0.633–0.893 0.001 0.593–0.964 0%, 0 0.813
Quality assessment
Low quality 3 0.627 0.383–1.026 0.063 0.212–1.823 0%, 0 0.936
High quality 5 0.804 0.704–0.917 0.001 0.668–0.973 0%, 0 0.594
All-cause mortality at 28 days 3 0.810 0.709–0.926 0.002 0.605–1.085 0%, 0 0.576
Length of hospital stay
Overall 17 −0.809 −1.601, −0.017 0.045 −3.219, 1.601 99.9%, 1.1291 < 0.001
World Bank classification
Low income 2 1.200 1.187, 1.213 < 0.001 1.114, 1.286 0%, 0 0.533
Lower-middle income 11 −1.490 −3.161, 0.181 0.081 −6.983, 4.003 87.8%, 5.3499 < 0.001
Upper-middle income 3 −0.854 −5.534, 3.827 0.721 −19.783, 18.076 83.9%, 13.6536 0.002
High income 1 2.000 −14.950, 18.950 0.817
Quality assessment
Low quality 5 −1.814 −4.910, 1.282 0.251 −10.261, 6.633 68.8%, 6.7612 0.012
High quality 12 −0.682 −1.562, 0.198 0.129 −3.221, 1.857 99.9%, 1.1288 < 0.001
Fully breast-fed at hospital discharge
Overall 7 1.263 0.910–1.752 0.163 0.417–3.824 94.9%, 0.1772 < 0.001
World Bank classification
Low income 1 1.000 0.964–1.038 0.985
Lower-middle income 5 1.331 1.171–1.513 < 0.001 1.087–1.695 12.9%, 0.0025 0.332
High income 1 1.204 0.844–1.718 0.307
Quality assessment
Low quality 3 1.356 1.171–1.570 < 0.001 0.976–1.824 0%, 0 0.447
High quality 4 1.188 0.715–1.974 0.506 0.198–7.124 95.9%, 0.2496 < 0.001
Weight gain rate
Overall 17 0.955 0.448, 1.461 < 0.001 −1.312, 3.221 97.2%, 1.0759 < 0.001
World Bank classification
Low income 2 1.071 −1.408, 3.549 0.397 −26.723, 28.864 99.6%, 3.1858 < 0.001
Lower-middle income 10 1.151 0.762, 1.541 < 0.001 −0.240, 2.542 88.6%, 0.3386 < 0.001
Upper-middle income 3 0.620 −0.119, 1.358 0.100 −2.443, 3.683 89.2%, 0.3647 < 0.001
High income 2 0.254 −0.171, 0.678 0.242 −2.498, 3.005 0%, 0 0.390
Quality assessment
Low quality 6 1.236 0.610, 1.862 < 0.001 −0.812, 3.285 89.0%, 0.5329 < 0.001
High quality 11 0.807 0.128, 1.487 0.020 −1.825, 3.440 98.1%, 1.2753 < 0.001
Length gain rate
Overall 5 1.281 0.056, 2.505 0.041 −2.895, 5.456 97.1%, 1.8706 < 0.001
World Bank classification
Lower-middle income 4 1.619 0.089, 3.149 0.038 −3.858, 7.096 97.8%, 2.3524 < 0.001
High income 1 0.000 −0.521, 0.521 0.999
Quality assessment
Low quality 1 5.756 4.853, 6.658 < 0.001
High quality 4 0.269 0.066, 0.472 0.009 −0.060, 0.598 0%, 0 0.402
Rate of head circumference gain
Overall 7 0.891 0.262, 1.520 0.006 −1.256, 3.038 93.9%, 0.6672 < 0.001
World Bank classification
Lower-middle income 5 0.903 0.021, 1.786 0.045 −2.094, 3.900 95.8%, 0.9623 < 0.001
Upper-middle income 1 0.994 0.623, 1.365 < 0.001
High income 1 0.761 0.220, 1.301 0.006
Quality assessment
Low quality 2 2.065 −0.463, 4.592 0.109 −26.133, 30.263 98.1%, 3.2624 < 0.001
High quality 5 0.457 0.038, 0.876 0.033 −0.865, 1.779 80.7%, 0.1809 < 0.001

Of the 8 studies assessing in-hospital mortality, 3 high-impact publications specifically reported data on 28-day all-cause mortality. Pooled analysis of these studies showed that neonates receiving KMC experienced a significantly lower risk of death within 28 days compared to those receiving conventional care [RR (95% CI) = 0.810 (0.709–0.926), 95% PI: 0.605–1.085; I2 = 0%] (Table 2, Figure 2B). However, due to the limited number of studies available for this outcome, subgroup analysis was not performed.

Forest plots of in-hospital mortality (A) and all-cause mortality at 28 days (B) after kangaroo mother care for preterm or low birth weight infants.

Forest plots labeled A and B display risk ratios with confidence intervals for different studies. Plot A includes eight studies, and Plot B includes three studies. Both show a common effect model with heterogeneity statistics. Risk ratios range from less than one to over one, indicating variable outcomes between experimental and control groups. Length of hospital stay and fully breast-fed at hospital discharge

17 studies investigated the influence of KMC on the duration of hospitalization among preterm and/or LBW infants. The meta-analysis revealed that neonates who received KMC experienced a significantly shorter hospital stay compared to those provided with conventional care [MD (95% CI) = −0.809 (−1.601, −0.017), 95% PI: −3.219, 1.601; I2 = 99.9%] (Table 2, Figure 3A). Notably, subgroup analysis showed that in low-income countries, infants receiving KMC had a longer hospital stay relative to those under conventional care [MD (95% CI) = 1.200 (1.187, 1.213), 95% PI: 1.114, 1.286; I2 = 0%]. In other subgroup analyses, no notable differences in hospitalization duration were identified between the two groups (all p > 0.05) (Table 2, Supplementary Figure S2).

Forest plots of length of hospital stay (A) and fully breast-fed at hospital discharge (B) after kangaroo mother care for preterm or low birth weight infants.

Forest plots illustrating two separate analyses. Graph A shows mean differences with 95% confidence intervals for multiple studies, with a summary effect near zero. Graph B displays risk ratios and 95% confidence intervals, indicating a summary risk ratio above one. Each graph includes a list of studies, statistical data, and weights. Both graphs use a random effects model and provide prediction intervals and heterogeneity statistics.

Exclusive breastfeeding rates at discharge were examined in 7 studies comparing KMC with conventional care. The pooled analysis indicated no difference in exclusive breastfeeding rates between the two groups [RR (95% CI) = 1.263 (0.910–1.752), 95% PI: 0.417–3.824; I2 = 94.9%] (Table 2, Figure 3B). Subgroup analyses, however, revealed that in lower-middle-income countries or in studies classified as low quality, neonates receiving KMC had higher exclusive breastfeeding rates at discharge compared to those receiving conventional care (all p < 0.05). No significant differences were observed in other subgroups (all p > 0.05) (Table 2, Supplementary Figure S3).

 Rate of weight, length and head circumference gain

17 studies evaluated the impact of KMC on weight gain in hospitalized neonates. The pooled analysis demonstrated that neonates receiving KMC had a faster rate of weight gain compared with those receiving conventional care [SMD (95% CI) = 0.955 (0.448, 1.461), 95% PI: −1.312, 3.221; I2 = 97.2%] (Table 2, Figure 4A). This significant finding was validated only in lower-middle-income countries [SMD (95% CI) = 1.151 (0.762, 1.541), 95% PI: −0.240, 2.542; I2 = 88.6%], while no notable differences were identified in other income settings. Subgroup analyses stratified by study quality demonstrated that the accelerated weight gain in the KMC group was consistently observed in both high- and low-quality studies (all p < 0.05) (Table 2, Supplementary Figure S4).

Forest plots of weight gain rate (A), length gain rate (B) and rate of head circumference gain (C) after kangaroo mother care for preterm or low birth weight infants.

Forest plots labeled A, B, and C display meta-analysis results. Each plot includes study names, sample sizes, means, standard deviations, and standardized mean differences (SMD) with confidence intervals. Plot A shows overall SMD of 0.95, Plot B shows 1.28, and Plot C shows 0.54. Prediction intervals and heterogeneity metrics are provided below each plot. Plots feature blue squares representing SMD for individual studies, with line connected through a vertical axis, and a diamond representing overall effect size.

The rate of length growth was assessed in 5 studies. The pooled findings showed that neonates receiving KMC experienced a more rapid increase in length compared to those receiving conventional care [SMD (95% CI) = 1.281 (0.056, 2.505), 95% PI: −2.895, 5.456; I2 = 97.1%] (Table 2, Figure 4B). This association was confirmed in lower-middle-income countries [SMD (95% CI) = 1.619 (0.089, 3.149), 95% PI: −3.858, 7.096; I2 = 97.8%]. Subgroup analyses based on study quality indicated that the faster rate of length gain in the KMC group was observed in high-quality studies [SMD (95% CI) = 0.269 (0.066, 0.472), 95% PI: −0.060, 0.598; I2 = 0%] (Table 2, Supplementary Figure S5).

7 studies reported on the rate of head circumference gain. The meta-analysis indicated that neonates receiving KMC had a faster rate of head circumference gain compared with those receiving conventional care [SMD (95% CI) = 0.891 (0.262, 1.520), 95% PI: −1.256, 3.038; I2 = 93.9%] (Table 2, Figure 4C). This significant result was validated in lower-middle-income countries [SMD (95% CI) = 0.903 (0.021, 1.786), 95% PI: −2.094, 3.900; I2 = 95.8%]. Subgroup analyses by study quality revealed that the accelerated head circumference growth associated with KMC was observed exclusively in high-quality studies [SMD (95% CI) = 0.457 (0.038, 0.876), 95% PI: −0.865, 1.779; I2 = 80.7%] (Table 2, Supplementary Figure S6).

 Overall and subgroup analysis of the safety outcomes Hypothermia and hyperthermia

19 studies investigated the incidence of hypothermia in both KMC and conventional care groups. The pooled analysis revealed that neonates receiving KMC had a significantly lower risk of hypothermia compared with those receiving conventional care [RR (95% CI) = 0.482 (0.363–0.638), 95% PI: 0.191–1.212; I2 = 73.4%] (Table 3, Figure 5A). This protective effect was consistently observed across low-income or lower-middle-income countries, as well as in both high-quality and low-quality studies (all p < 0.05) (Table 3, Supplementary Figure S7).

Pooled effect and subgroup analysis of the safety outcomes of kangaroo mother care for preterm or low birth weight infants.

Outcomes and subgroups Number of studies Meta-analysis Heterogeneity
RR 95% CI p value 95% PI I2, Tau2 p value
Hypothermia
Overall 19 0.482 0.363–0.638 < 0.001 0.191–1.212 73.4%, 0.1724 < 0.001
World Bank classification
Low income 2 0.784 0.719–0.854 < 0.001 0.190–3.408 33.7%, 0.0064 0.220
Lower-middle income 13 0.303 0.191–0.483 < 0.001 0.073–1.263 67.1%, 0.3726 < 0.001
Upper-middle income 1 0.580 0.332–1.016 0.057
High income 3 0.681 0.194–2.395 0.549 0.007–69.296 59.8%, 0.7425 0.083
Quality assessment
Low quality 6 0.497 0.262–0.942 0.032 0.077–3.213 71.9%, 0.4210 0.003
High quality 13 0.456 0.325–0.642 < 0.001 0.175–1.194 75.5%, 0.1645 < 0.001
Hyperthermia
Overall 6 0.689 0.535–0.886 0.004 0.506–0.954 0%, 0 0.757
World Bank classification
Low income 1 0.200 0.010–4.165 0.299
Lower-middle income 2 0.796 0.507–1.252 0.324 0.044–14.884 0%, 0 0.654
High income 3 0.649 0.482–0.875 0.005 0.351–1.244 0%, 0 0.532
Quality assessment
Low quality 1 0.703 0.499–0.992 0.045
High quality 5 0.681 0.485–0.956 0.027 0.423–1.111 0%, 0 0.624
Apnea
Overall 11 0.547 0.415–0.721 < 0.001 0.156–1.823 47.4%, 0.2453 0.040
World Bank classification
Low income 1 0.785 0.486–1.266 0.321
Lower-middle income 9 0.418 0.294–0.594 < 0.001 0.108–1.759 45.0%, 0.2852 0.068
High income 1 3.273 0.388–27.580 0.276
Quality assessment
Low quality 2 0.371 0.084–1.637 0.191 – 79.4%, 0.9194 0.028
High quality 9 0.593 0.433–0.813 0.001 0.163–2.114 41.9%, 0.2328 0.088
Sepsis
Overall 14 0.557 0.434–0.714 < 0.001 0.298–0.982 16.8%, 0.0528 0.270
World Bank classification
Low income 1 0.972 0.611–1.547 0.906
Lower-middle income 9 0.403 0.283–0.576 < 0.001 0.281–0.662 0%, 0 0.539
Upper-middle income 3 0.572 0.283–1.157 0.120 0.117–2.757 0%, 0 0.515
High income 1 0.511 0.189–1.383 0.186
Quality assessment
Low quality 4 0.373 0.199–0.698 0.002 0.076–2.172 21.1%, 0.1288 0.284
High quality 10 0.604 0.460–0.793 < 0.001 0.306–1.080 17.9%, 0.0495 0.278
Necrotizing enterocolitis
Overall 5 0.575 0.358–0.923 0.022 0.185–1.819 17.3%, 0.0807 0.304
World Bank classification
Low income 1 1.430 0.546–3.743 0.466
Lower-middle income 3 0.410 0.227–0.739 0.003 0.112–1.494 0%, 0 0.979
High income 1 0.409 0.039–4.272 0.455
Quality assessment
Low quality 1 0.400 0.083–1.926 0.253
High quality 4 0.598 0.364–0.982 0.042 0.099–3.897 35.2%, 0.1937 0.201
Hypoglycemia
Overall 5 0.477 0.107–2.128 0.332 0.006–35.596 81.0%, 1.8303 < 0.001
World Bank classification
Lower-middle income 4 0.320 0.061–1.664 0.175 0.002–57.091 84.7%, 1.9463 < 0.001
High income 1 5.577 0.274–113.504 0.264
Quality assessment
High quality 5 0.477 0.107–2.128 0.332 0.006–35.596 81.0%, 1.8303 < 0.001

Forest plots of hypothermia (A) and hyperthermia (B) after kangaroo mother care for preterm or low birth weight infants.

Forest plots titled “A” and “B” compare risk ratios of various studies. Each plot lists studies alongside columns for experimental and control events, total events, risk ratios, confidence intervals, and weights. Plot A includes a random effects model showing a pooled risk ratio of 0.48. Plot B uses a common effect model with a pooled risk ratio of 0.69. Studies and individual risk ratio estimates are depicted by squares on a logarithmic scale, with horizontal lines representing confidence intervals. Both include heterogeneity measures.

The prevalence of hyperthermia was examined in 6 studies. The meta-analysis indicated that KMC was associated with a lower incidence of hyperthermia in neonates compared with conventional care [RR (95% CI) = 0.689 (0.535–0.886), 95% PI: 0.506–0.954; I2 = 0%] (Table 3, Figure 5B). Subgroup analyses further showed that this reduced incidence of hyperthermia with KMC was consistently observed in high-income countries as well as in high-quality or low-quality studies (all p < 0.05) (Table 3, Supplementary Figure S8).

 Apnea and sepsis

11 studies examined the prevalence of apnea in neonates receiving KMC compared to those managed with conventional care. Meta-analysis results revealed that KMC was associated with a significantly reduced risk of apnea [RR (95% CI) = 0.547 (0.415–0.721), 95% PI: 0.156–1.823; I2 = 47.4%] (Table 3, Figure 6A). Subgroup analyses showed that this reduction was significant only in lower-middle-income countries [RR (95% CI) = 0.418 (0.294–0.594), 95% PI: 0.108–1.759; I2 = 45.0%] or in studies of high quality [RR (95% CI) = 0.593 (0.433–0.813), 95% PI: 0.163–2.114; I2 = 41.9%], while no significant findings were detected in other subgroups (all p > 0.05) (Table 3, Supplementary Figure S9).

Forest plots of apnea (A), sepsis (B), necrotizing enterocolitis (C) and hypoglycemia (D) after kangaroo mother care for preterm or low birth weight infants.

Forest plots in four panels labeled A, B, C, and D, displaying meta-analysis results. Each panel lists studies with experimental and control groups, displaying risk ratios and confidence intervals. Panel A shows a common effect model with moderate heterogeneity, panel B with low heterogeneity, panel C with very low heterogeneity, and panel D with high heterogeneity, using a random effects model. The x-axis represents risk ratios on a logarithmic scale. Each plot includes a diamond symbol summarizing the overall effect.

The incidence of sepsis among hospitalized neonates was reported in 14 studies. The pooled analysis indicated that infants managed with KMC experienced a lower risk of sepsis compared to those receiving conventional care [RR (95% CI) = 0.557 (0.434–0.714), 95% PI: 0.298–0.982; I2 = 16.8%] (Table 3, Figure 6B). However, this significant association was confined to lower-middle-income countries [RR (95% CI) = 0.403 (0.283–0.576), 95% PI: 0.281–0.662; I2 = 0%], with no meaningful differences detected in other income classifications. Subgroup analyses stratified by study quality further confirmed that the reduction in sepsis incidence was consistently evident in both high-quality and low-quality studies (all p < 0.05) (Table 3, Supplementary Figure S10).

 NEC and hypoglycemia

5 studies assessed the prevalence of NEC in KMC and conventional care groups. The pooled results indicated that KMC was associated with a significantly decreased risk of NEC [RR (95% CI) = 0.575 (0.358–0.923), 95% PI: 0.185–1.819; I2 = 17.3%] (Table 3, Figure 6C). Subgroup analyses revealed that this protective effect was significant only in lower-middle-income countries [RR (95% CI) = 0.410 (0.227–0.739), 95% PI: 0.112–1.494; I2 = 0%] or in studies classified as high quality [RR (95% CI) = 0.598 (0.364–0.982), 95% PI: 0.099–3.897; I2 = 35.2%] (Table 3, Supplementary Figure S11).

Regarding neonatal hypoglycemia, 5 studies investigated its prevalence in KMC and conventional care groups. The meta-analysis found no evidence of a significant reduction in hypoglycemia rates among neonates receiving KMC compared to conventional care [RR (95% CI) = 0.477 (0.107–2.128), 95% PI: 0.006–35.596; I2 = 81.0%] (Table 3, Figure 6D). Subgroup analyses based on the World Bank classification or quality assessment also failed to identify any statistically significant differences (all p > 0.05) (Table 3, Supplementary Figure S12).

 Trial sequential analysis results

Analysis of efficacy outcomes revealed that the cumulative Z-curves for in-hospital mortality, 28-day all-cause mortality, weight gain velocity, and head circumference growth surpassed the trial sequential monitoring or RIS thresholds. These findings indicated that the evidence supporting these endpoints is robust and conclusive, eliminating the need for additional trials. Conversely, the cumulative Z-curves for hospital stay duration, fully breast-fed at hospital discharge, and length gain rate did not meet the RIS and trial sequential monitoring boundaries, suggesting that the evidence for these measures remains uncertain and may be prone to false-positive results (Figure 7). Regarding safety outcomes, we observed that the cumulative Z-curves for all outcomes, except hypoglycemia, crossed either the RIS boundaries or the trial sequential monitoring boundaries (Figure 8).

Trial sequential analysis of the efficacy outcomes after kangaroo mother care for preterm or low birth weight infants. (A) In-hospital mortality; (B) all-cause mortality at 28 days; (C) length of hospital stay; (D) fully breast-fed at hospital discharge; (E) weight gain rate; (F) length gain rate; (G) rate of head circumference gain. Uppermost and lowermost red curves represent trial sequential monitoring boundary lines for benefit and harm, respectively. Inner red lines represent the futility boundary. Blue line represents evolution of cumulative Z-score. Horizontal green lines represent the conventional boundaries for statistical significance. Cumulative Z-curve crossing the trial sequential monitoring boundary or the RIS boundary provides firm evidence of effect.

Seven graphs labeled A to G illustrate required information size versus cumulative data for different scenarios. Each graph includes red and blue lines representing different variables, with annotated required information sizes ranging from 701 to 7522. The x-axes feature interventions labeled at specific intervals, while the y-axes show z-scores and cumulative data. The graphs indicate the correlation between measured variables and required information size.

Trial sequential analysis of the safety outcomes after kangaroo mother care for preterm or low birth weight infants. (A) Hypothermia; (B) hyperthermia; (C) apnea; (D) sepsis; (E) necrotizing enterocolitis; (F) Hypoglycemia. Uppermost and lowermost red curves represent trial sequential monitoring boundary lines for benefit and harm, respectively. Inner red lines represent the futility boundary. Blue line represents evolution of cumulative Z-score. Horizontal green lines represent the conventional boundaries for statistical significance. Cumulative Z-curve crossing the trial sequential monitoring boundary or the RIS boundary provides firm evidence of effect.

Graphs A to F display cumulative Z-score analyses with required information sizes indicated: A (8477), B (3422), C (4022), D (1954), E (4264), F (13726). Each shows trends with a Z-curve amidst data series, focusing on the primary results needed for statistical significance. Each graph highlights data points and intersections with the required information threshold. Sensitivity analysis and publication bias

Sensitivity analyses and evaluations for publication bias were conducted for outcomes derived from at least 8 studies. To assess the impact of individual studies on the pooled results, a leave-one-out sensitivity analysis was conducted. For the pooled estimate of hospital stay duration, the proximity of the 95% CI to zero suggested that removing several individual studies could alter the statistical significance of the results. Additionally, sensitivity analyses for the remaining endpoints demonstrated relative robustness and stability (Supplementary Figure S13). Begg's and Egger's tests indicated potential publication bias among studies reporting the outcome of weight gain rate (Begg's test: p = 0.202; Egger's test: p = 0.046). However, subsequent analysis utilizing the trim-and-fill method showed no substantial changes in the direction and significance of the pooled results before and after adjustment, suggesting that the presence of publication bias did not substantially affect the conclusions. No evidence of significant publication bias was found for the remaining outcomes. Detailed funnel plots are presented in Supplementary Figure S14.

 Discussion

The findings of this meta-analysis indicated that compared with conventional care, KMC significantly reduced in-hospital mortality and 28-day all-cause mortality among preterm and/or LBW infants. Furthermore, KMC was associated with shorter hospital stay and significantly improved growth parameters during hospitalization, including increased rates of weight gain, length growth, and head circumference growth. In terms of clinical safety, KMC was associated with lower risks of hypothermia, hyperthermia, apnea, sepsis, and NEC during hospitalization. However, no significant differences were identified between KMC and conventional care in the rates of exclusive breastfeeding at discharge and the incidence of neonatal hypoglycemia.

Our results align with earlier comprehensive reviews, highlighting that KMC plays a significant role in lowering neonatal death rates, shortening hospital stays, promoting faster growth, and mitigating the risk of various complications (8–10, 50, 51). Neonatal mortality remains the most clinically significant and patient-centered outcome in this context. The mechanisms underlying the benefits of KMC are multifaceted. By maintaining close physical proximity between mother and infant immediately after birth, the baby is more likely to be colonized by the mother's beneficial microbiota and to initiate breastfeeding earlier. Additionally, reduced handling of the infant by others helps lower the likelihood of infections (23, 30, 48). Continuous maternal observation, more frequent checks of the baby's glucose levels, and the elimination of stress (52) associated with separation from the mother may also contribute to the observed decrease in mortality rates. Research by Charpak et al. (53) suggests that the skin-to-skin positioning of KMC strengthens the maternal-infant bond, enhances the infant's reliance on the mother (54), and provides necessary stimulation to prevent apnea episodes (50). Simultaneously, this practice ensures sufficient warmth (55) to guard against deaths caused by hypothermia in preterm newborns (56).

Previous meta-analysis integrating relevant research have shown that KMC significantly shortens the duration of hospitalization when compared to standard care (51), a conclusion that aligns with the results of our study. Early discharge from neonatal units alleviates overcrowding, thereby decreasing the risk of hospital-acquired infections and lessening the financial burden on families. Moreover, it contributes to the reduction of overall healthcare costs (33, 57). Evidence suggested that KMC helps diminish pain responses during procedures such as heel-prick blood sampling in preterm infants, extends sleep duration, and supports growth and development, all of which contribute to a reduced hospital stay (58, 59). Among the key criteria for discharging preterm and/or LBW infants is adequate weight gain. Our study further confirmed that KMC promoted accelerated growth in weight, length, and head circumference, which may explain the observed reduction in hospital stay. Consistent with our results, prior studies have demonstrated that KMC not only reduces the time preterm infants spend in the hospital but also plays a pivotal role in fostering their overall growth and developmental progress (51, 60).

Hypothermia remains a well-recognized safety concern in preterm deliveries, whereas the risks associated with hyperthermia have been comparatively underexplored. In our analysis, the incidence of both hypothermia and hyperthermia was significantly reduced among neonates receiving KMC compared with those managed with conventional care, consistent with findings from previous studies involving infants born between 280-326 weeks of gestation (36). Supporting this, Mehler et al. (61) demonstrated that neonates exposed to 1 h of KMC in the delivery room had a higher mean skin temperature upon admission to the neonatal intensive care unit (NICU) (36.6 °C) compared to those receiving conventional care (36.1 °C). The physiological benefits of KMC are likely mediated through stabilization of cardiac and pulmonary function via the autonomic nervous system (62), coupled with enhanced microcirculation and improved tissue perfusion, resulting in better thermoregulation in LBW and/or preterm infants (63). Collectively, these findings provide robust evidence that early initiation of KMC is not only safe but also enhances thermoregulation in this vulnerable population.

A systematic review conducted in 2020 involving 416 preterm neonates identified a significant reduction in apneic episodes among infants receiving KMC (50). The findings of the present study further reinforce this evidence. Recent research has demonstrated enhanced cardiorespiratory stability in very preterm infants who underwent 6 h of KMC compared to those receiving conventional care immediately after birth (64). These results are consistent with earlier research suggesting that skin-to-skin contact contributes to improved respiratory function by supporting thermoregulation, attenuating stress responses, and fostering synchronized cardiorespiratory activity (65). Additionally, in line with the findings of Tas-Arslan et al. (66) this study suggested that KMC appears to be a safe intervention for neonates with respiratory compromise, potentially without increasing the likelihood of treatment failure.

A critical safety outcome associated with KMC is the significant reduction in hospital-acquired infections, including sepsis and NEC. These findings align with prior meta-analyses, which have documented a 65% decrease in nosocomial infections (67) and a 50% reduction in severe infections (68) among stable newborns managed with KMC. Such reductions in infection rates have been corroborated by multi-country studies, where improved survival free from infections was attributed to sustained maternal-infant contact, increased breastfeeding rates, and reduced exposure to hospital-related pathogens (22). While some critics have raised concerns about the potential limitations of KMC in settings with overcrowded facilities and inadequate nurse-to-patient ratios (69), the current multi-center trial, encompassing NICUs with varying levels of resources and capacity, consistently demonstrated infection prevention benefits across diverse healthcare environments (70). Furthermore, the degree to which KMC reduces infection risks may be influenced by specific nosocomial factors within the clinical setting. Risks such as exposure to contaminated fluids or inappropriate antibiotic use remain relevant regardless of the timing of KMC initiation. To optimize outcomes, infection control measures, such as rigorous hand hygiene practices among KMC providers and healthcare staff, should be prioritized and reinforced prior to implementing KMC programs (24).

Our subgroup analysis revealed that KMC significantly reduced in-hospital mortality among preterm and/or LBW infants in lower-middle-income countries. Additionally, KMC was associated with higher rates of exclusive breastfeeding at discharge, enhanced growth in weight, length, and head circumference, and a reduced incidence of hypothermia, apnea, sepsis, and NEC. These findings carry important implications for health policy, particularly in resource-limited settings. However, as the majority of studies included in this analysis were conducted in lower-middle-income countries, with limited representation from low-income, upper-middle-income, and high-income regions, the current evidence is insufficient to draw robust comparisons regarding the clinical efficacy and safety of KMC across diverse economic contexts. This underscores the need for future research to investigate these variations and provide a more comprehensive understanding of its impact in different income settings.

This study is subject to several limitations. First, data regarding race, ethnicity, and sex were not incorporated into the analysis due to inconsistent or absent reporting in the included studies. Second, the specific effects of immediate, early, or continuous KMC could not be adequately assessed, as the majority of included studies did not clearly distinguish between different types of KMC. Third, many RCTs analyzed had limited sample sizes, leading to small study effects and insufficient statistical power for certain outcomes, with some trials reporting no events in either group. Fourth, a lack of standardized definitions for KMC and inconsistent implementation across intervention and control groups further contributed to heterogeneity in the meta-analysis, potentially underestimating the true impact of KMC. Standardized reporting of key definitions and practices in future RCTs is essential to enhance comparability across studies. Fifth, the inability to achieve complete blinding of caregivers, given the inherently visible nature of skin-to-skin contact, likely introduced performance bias. This methodological limitation may have influenced the overall quality of some studies included in the analysis.

 Conclusion

In conclusion, our findings indicated that KMC is beneficial for preterm and/or LBW infants, as evidenced by reductions in neonatal in-hospital mortality and 28-day all-cause mortality, shorter hospital stays, and accelerated growth in weight, length, and head circumference. Additionally, KMC was associated with a decreased risk of AEs, including hypothermia, hyperthermia, apnea, sepsis, and NEC. Subgroup analyses further highlighted the substantial clinical effectiveness and favorable safety profile of KMC, particularly in resource-limited settings within lower-middle-income countries. Future research should focus on evaluating the efficacy and safety of KMC in clinical practice across countries with varying income levels.

 Data availability statement

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.

 Author contributions

LL: Writing – original draft, Formal analysis, Investigation, Data curation, Software, Conceptualization. QT: Visualization, Methodology, Formal analysis, Investigation, Writing – original draft. HL: Writing – review & editing, Conceptualization, Validation, Investigation, Supervision.

 Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

 Generative AI statement

The author(s) declared that generative AI was not used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

 Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

 Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmed.2025.1736973/full#supplementary-material

 References Milner KM Neal EF Roberts G Steer AC Duke T. Long-term neurodevelopmental outcome in high-risk newborns in resource-limited settings: a systematic review of the literature. Paediatr Int Child Health. (2015) 35:227–42. doi: 10.1179/2046905515Y.000000004326138273 Lawn JE Ohuma EO Bradley E Idueta LS Hazel E Okwaraji YB . Small babies, big risks: global estimates of prevalence and mortality for vulnerable newborns to accelerate change and improve counting. Lancet. (2023) 401:1707–19. doi: 10.1016/S0140-6736(23)00522-637167989 Tumukunde V Medvedev MM Tann CJ Mambule I Pitt C Opondo C . Effectiveness of kangaroo mother care before clinical stabilisation versus standard care among neonates at five hospitals in Uganda (OMWaNA): a parallel-group, individually randomised controlled trial and economic evaluation. Lancet. (2024) 403:2520–32. doi: 10.1016/S0140-6736(24)00064-338754454 Bhutta ZA Das JK Bahl R Lawn JE Salam RA Paul VK . Can available interventions end preventable deaths in mothers, newborn babies, and stillbirths, and at what cost? Lancet. (2014) 384:347–70. doi: 10.1016/S0140-6736(14)60792-324853604 Charpak N Ruiz JG Zupan J Cattaneo A Figueroa Z Tessier R . Kangaroo mother care: 25 years after. Acta Paediatr. (2005) 94:514–22. doi: 10.1111/j.1651-2227.2005.tb01930.x16188735 Nurian M Mashdberd Y Yaghmaei F Baghbani AA Heydarzadeh H. Effects of kangaroo and routine care on physiologic parameters of low-birth-weight infants. Adv Nurs Midwifery. (2009) 18:19–24. https://doi.org/10.22037/anm.v18i65.1335 Scime NV Gavarkovs AG Chaput KH. The effect of skin-to-skin care on postpartum depression among mothers of preterm or low birthweight infants: a systematic review and meta-analysis. J Affect Disord. (2019) 253:376–84. doi: 10.1016/j.jad.2019.04.10131078838 Conde-Agudelo A Díaz-Rossello JL. Kangaroo mother care to reduce morbidity and mortality in low birthweight infants. Cochrane Database Syst Rev. (2016) 2016:Cd002771. doi: 10.1002/14651858.CD002771.pub412804436 Sivanandan S Sankar MJ. Kangaroo mother care for preterm or low birth weight infants: a systematic review and meta-analysis. BMJ Glob Health. (2023) 8:e010728. doi: 10.1136/bmjgh-2022-01072837277198 Minotti C Jost K Aghlmandi S Schlaeppi C Sieswerda E van Werkhoven CH . All-cause mortality and infection-related outcomes of hospital-initiated kangaroo care versus conventional neonatal care for low-birthweight infants: a systematic review and meta-analysis. Lancet Child Adolesc Health. (2025) 9:470–83. doi: 10.1016/S2352-4642(25)00130-040441171 Page MJ McKenzie JE Bossuyt PM Boutron I Hoffmann TC Mulrow CD . The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. (2021) 372:n71. doi: 10.1136/bmj.n7133782057 Jadad AR Moore RA Carroll D Jenkinson C Reynolds DJ Gavaghan DJ . Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials. (1996) 17:1–12. doi: 10.1016/0197-2456(95)00134-48721797 Bowden J Tierney JF Copas AJ Burdett S. Quantifying, displaying and accounting for heterogeneity in the meta-analysis of RCTs using standard and generalised Q statistics. BMC Med Res Methodol. (2011) 11:41. doi: 10.1186/1471-2288-11-4121473747 IntHout J Ioannidis JP Rovers MM Goeman JJ. Plea for routinely presenting prediction intervals in meta-analysis. BMJ Open. (2016) 6:e010247. doi: 10.1136/bmjopen-2015-01024727406637 Higgins JP Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med. (2002) 21:1539–58. doi: 10.1002/sim.118612111919 World Bank. World Bank Country and Lending Groups-World Bank Data Help Desk. Available online at: https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country%02and-lending-groups (Accessed September 3, 2025). Begg CB Mazumdar M. Operating characteristics of a rank correlation test for publication bias. Biometrics. (1994) 50:1088–101. doi: 10.2307/25334467786990 Egger M Davey Smith G Schneider M Minder C. Bias in meta-analysis detected by a simple, graphical test. BMJ. (1997) 315:629–34. doi: 10.1136/bmj.315.7109.629 Wetterslev J Jakobsen JC Gluud C. Trial sequential analysis in systematic reviews with meta-analysis. BMC Med Res Methodol. (2017) 17:39. doi: 10.1186/s12874-017-0315-728264661 Acharya N Singh RR Bhatta NK Poudel P. Randomized control trial of Kangaroo mother care in low birth weight babies at a Tertiary Level Hospital. J Nepal Paediatr Soc. (2014) 34:18–23. doi: 10.3126/jnps.v34i1.8960 Ali SM Sharma J Sharma R Alam S. Kangaroo mother care as compared to conventional care for low birth weight babies. Dicle Med J. (2009) 36:155–60. Arya S Naburi H Kawaza K Newton S Anyabolu CH Bergman N . Immediate “Kangaroo Mother Care” and survival of infants with low birth weight. N Engl J Med. (2021) 384:2028–38. doi: 10.1056/NEJMoa202648634674298 Boo NY Jamli FM. Short duration of skin-to-skin contact: effects on growth and breastfeeding. J Paediatr Child Health. (2007) 43:831–6. doi: 10.1111/j.1440-1754.2007.01198.x17803670 Brotherton H Gai A Kebbeh B Njie Y Walker G Muhammad AK . Impact of early kangaroo mother care versus standard care on survival of mild-moderately unstable neonates < 2000 grams: a randomised controlled trial. EClinicalMedicine. (2021) 39:101050. doi: 10.1016/j.eclinm.2021.101050 Çaka SY Topal S Yurttutan S Aytemiz S Çikar Y Sari M. Effects of kangaroo mother care on feeding intolerance in preterm infants. J Trop Pediatr. (2023) 69:fmad015. doi: 10.1093/tropej/fmad01536897067 Chi Luong K Long Nguyen T Huynh Thi DH Carrara HP Bergman NJ. Newly born low birthweight infants stabilise better in skin-to-skin contact than when separated from their mothers: a randomised controlled trial. Acta Paediatr. (2016) 105:381–90. doi: 10.1111/apa.1316426303808 Chwo MJ Anderson GC Good M Dowling DA Shiau SH Chu DM . Randomized controlled trial of early kangaroo care for preterm infants: effects on temperature, weight, behavior, and acuity. J Nurs Res. (2002) 10:129–42. doi: 10.1097/01.JNR.0000347592.43768.46 de Ocampo FS Villanueva-Uy MET A. Randomized controlled trial of intermittent kangaroo mother care versus conventional care in increasing the rate of weight gain among low-birth-weight neonates. Acta Med Philipp. (2021) 55:873–79. doi: 10.47895/amp.v55i9.3757 Gathwala G Singh B Singh J. Effect of kangaroo mother care on physical growth, breastfeeding and its acceptability. Trop Doct. (2010) 40:199–202. doi: 10.1258/td.2010.09051320667921 Ghavane S Murki S Subramanian S Gaddam P Kandraju H Thumalla S. Kangaroo Mother Care in Kangaroo ward for improving the growth and breastfeeding outcomes when reaching term gestational age in very low birth weight infants. Acta Paediatr. (2012) 101:e545–9. doi: 10.1111/apa.1202323016710 Hake-Brooks SJ Anderson GC. Kangaroo care and breastfeeding of mother-preterm infant dyads 0-18 months: a randomized, controlled trial. Neonatal Netw. (2008) 27:151–9. doi: 10.1891/0730-0832.27.3.15118557262 Hoque MM Jahan N Rahman MM Saha LC Akhter RJ Chowdhury MA. Effectiveness of KMC on success of breast feeding in preterm low birth weight neonate. Acad J Ped Neonatol. (2017) 3:1–4. doi: 10.19080/AJPN.2017.02.555617 Kadam S Binoy S Kanbur W Mondkar JA Fernandez A. Feasibility of Kangaroo mother care in Mumbai. Indian J Pediatr. (2005) 72:35–8. doi: 10.1007/BF0276057815684446 Kristoffersen L Bergseng H Engesland H Bagstevold A Aker K Støen R. Skin-to-skin contact in the delivery room for very preterm infants: a randomised clinical trial. BMJ Paediatr Open. (2023) 7:e001831. doi: 10.1136/bmjpo-2022-00183136958792 Kumbhojkar S Mokase Y Sarawade S. Kangaroo Mother Care (KMC): an alternative to conventional method of care for low birth weight babies. Int J Health Sci Res. (2016) 6:36–42. Lode-Kolz K Hermansson C Linnér A Klemming S Hetland HB Bergman N . Immediate skin-to-skin contact after birth ensures stable thermoregulation in very preterm infants in high-resource settings. Acta Paediatr. (2023) 112:934–41. doi: 10.1111/apa.1659036333892 Lumbanraja SN. Influence of maternal factors on the successful outcome of kangaroo mother care in low birth-weight infants: a randomized controlled trial. J Neonatal Perinatal Med. (2016) 9:385–92. doi: 10.3233/NPM-16162828009335 Manzoor N Sehar S Afzal M Gilani SA. Effect of kangaroo mother care on exclusive breast feeding in low birth weight infants. Rawal Med J. (2023) 48:692–4. Mwendwa AC Musoke RN Wamalwa DC. Impact of partial kangaroo mother care on growth rates and duration of hospital stay of low birth weight infants at the Kenyatta National Hospital, Nairobi. East Afr Med J. (2012) 89:53–8. 26845812 Nimbalkar SM Patel VK Patel DV Nimbalkar AS Sethi A Phatak A. Effect of early skin-to-skin contact following normal delivery on incidence of hypothermia in neonates more than 1800 g: randomized control trial. J Perinatol. (2014) 34:364–8. doi: 10.1038/jp.2014.1524556982 Pratiwi IGAPE Soetjiningsih S Kardana IM. Effect of kangaroo method on the risk of hypothermia and duration of birth weight regain in low birth weight infants: a randomized controlled trial. Paediatr Indones. (2009) 49:253–8. doi: 10.14238/pi49.5.2009.253-8 Ramadan OME Alshammari AM Alruwaili AN Elsharkawy NB Alhaiti A Baraka NIM. Transforming neonatal nursing: a randomized controlled trial comparing kangaroo care and standard protocols for survival in preterm infants with respiratory distress syndrome. BMC Nurs. (2025) 24:430. doi: 10.1186/s12912-025-03088-840241073 Ramanathan K Paul VK Deorari AK Taneja U George G. Kangaroo Mother Care in very low birth weight infants. Indian J Pediatr. (2001) 68:1019–23. doi: 10.1007/BF02722345 Ricero-Luistro CP Villanueva-Uy MET Libadia AGI De Leon-Mendoza S. Effectiveness of Kangaroo Mother Care in reducing morbidity and mortality among preterm neonates on nasal continuous positive airway pressure: a randomized controlled trial. Acta Med Philipp. (2021) 55:1–7. doi: 10.47895/amp.v55i9.3784 Roberts KL Paynter C McEwan B. A comparison of kangaroo mother care and conventional cuddling care. Neonatal Netw. (2000) 19:31–5. doi: 10.1891/0730-0832.19.4.3111949100 Rojas MA Kaplan M Quevedo M Sherwonit E Foster L Ehrenkranz RA . Somatic growth of preterm infants during skin-to-skin care versus traditional holding: a randomized, controlled trial. J Dev Behav Pediatr. (2003) 24:163–8. doi: 10.1097/00004703-200306000-0000612806228 Singh P Arif F Kumar N. A hospital-based prospective study to compare kangaroo mother care (KMC) with the conventional method of care (CMC) in the management of low birth weight infants (LBWI) at tertiary care center. Int J Medi Public Health. (2024) 14:329–32. Suman RP Udani R Nanavati R. Kangaroo mother care for low birth weight infants: a randomized controlled trial. Indian Pediatr. (2008) 45:17–23. 18250500 Worku B Kassie A. Kangaroo mother care: a randomized controlled trial on effectiveness of early kangaroo mother care for the low birthweight infants in Addis Ababa, Ethiopia. J Trop Pediatr. (2005) 51:93–7. doi: 10.1093/tropej/fmh08515840760 Montealegre-Pomar A Bohorquez A Charpak N. Systematic review and meta-analysis suggest that Kangaroo position protects against apnoea of prematurity. Acta Paediatr. (2020) 109:1310–6. doi: 10.1111/apa.1516131916621 Narciso LM Beleza LO Imoto AM. The effectiveness of Kangaroo Mother Care in hospitalization period of preterm and low birth weight infants: systematic review and meta-analysis. J Pediatr (Rio J). (2022) 98:117–25. doi: 10.1016/j.jped.2021.06.00434274324 Forde D Deming DD Tan JC Phillips RM Fry-Bowers EK Barger MK . Oxidative stress biomarker decreased in preterm neonates treated with Kangaroo Mother Care. Biol Res Nurs. (2020) 22:188–96. doi: 10.1177/109980041990023131973579 Charpak N Ruiz JG. Latin American clinical epidemiology network series - Paper 9: the Kangaroo mother care method: from scientific evidence generated in Colombia to worldwide practice. J Clin Epidemiol. (2017) 86:125–8. doi: 10.1016/j.jclinepi.2016.05.01927765653 Zhang SH Yip WK Lim PF Goh MZ. Evidence utilization project: implementation of kangaroo care at neonatal ICU. Int J Evid Based Healthc. (2014) 12:142–50. doi: 10.1097/XEB.000000000000000924945956 Nimbalkar S Sadhwani N. Implementation of Kangaroo Mother Care - challenges and solutions. Indian Pediatr. (2019) 56:725–9. doi: 10.1007/s13312-019-1635-y31638001 Nyondo-Mipando AL Kinshella MW Hiwa T Salimu S Banda M Vidler M . Mothers' quality of life delivering kangaroo mother care at Malawian hospitals: a qualitative study. Health Qual Life Outcomes. (2021) 19:186. doi: 10.1186/s12955-021-01823-834321038 Sloan NL Camacho LW Rojas EP Stern C. Kangaroo mother method: randomised controlled trial of an alternative method of care for stabilised low-birthweight infants. Maternidad Isidro Ayora Study Team Lancet. (1994) 344:782–5. doi: 10.1016/S0140-6736(94)92341-8 Özdel D Sari HY. Effects of the prone position and kangaroo care on gastric residual volume, vital signs and comfort in preterm infants. Japan J Nurs Sci. (2020) 17:e12287. doi: 10.1111/jjns.1228731642602 Andreoli SP. 50 Years ago in The Journal of Pediatrics: congenital abnormalities of the urinary system, IV: valvular obstruction of the posterior urethra. J Pediatr. (2013) 163:186. doi: 10.1016/j.jpeds.2013.01.04723796339 Charpak N Montealegre-Pomar A Bohorquez A. Systematic review and meta-analysis suggest that the duration of Kangaroo mother care has a direct impact on neonatal growth. Acta Paediatr. (2021) 110:45–59. doi: 10.1111/apa.1548932683720 Mehler K Hucklenbruch-Rother E Trautmann-Villalba P Becker I Roth B Kribs A. Delivery room skin-to-skin contact for preterm infants-a randomized clinical trial. Acta Paediatr. (2020) 109:518–26. doi: 10.1111/apa.1497531423649 Sehgal A Nitzan I Jayawickreme N Menahem S. Impact of skin-to-skin parent-infant care on preterm circulatory physiology. J Pediatr. (2020) 222:91–7.e2. doi: 10.1016/j.jpeds.2020.03.04132389414 Miranda RM Cabral Filho JE Diniz KT Clough GF Alves JGB Lima GMS . Effect of Kangaroo position on microcirculation of preterm newborns: a controlled randomized clinical trial. J Pediatr (Rio J). (2022) 98:196–203. doi: 10.1016/j.jped.2021.05.01234454941 Linnér A Lode Kolz K Klemming S Bergman N Lilliesköld S Markhus Pike H . Immediate skin-to-skin contact may have beneficial effects on the cardiorespiratory stabilisation in very preterm infants. Acta Paediatr. (2022) 111:1507–14. doi: 10.1111/apa.1637135466432 Lee J Parikka V Lehtonen L Soukka H. Parent-infant skin-to-skin contact reduces the electrical activity of the diaphragm and stabilizes respiratory function in preterm infants. Pediatr Res. (2022) 91:1163–7. doi: 10.1038/s41390-021-01607-234088986 Tas Arslan F Akkoyun S Küçükoglu S Kocoglu-Tanyer D Konak M Soylu H. Effect of kangaroo mother care on cerebral oxygenation, physiological parameters, and comfort levels in late-premature infants: A randomized controlled trial. Midwifery. (2024) 137:104096. doi: 10.1016/j.midw.2024.10409639024964 Boundy EO Dastjerdi R Spiegelman D Fawzi WW Missmer SA Lieberman E . Kangaroo mother care and neonatal outcomes: a meta-analysis. Pediatrics. (2016) 137:e20152238. doi: 10.1542/peds.2015-223827329919 Lawn JE Mwansa-Kambafwile J Horta BL Barros FC Cousens S. 'Kangaroo mother care' to prevent neonatal deaths due to preterm birth complications. Int J Epidemiol. (2010) 39:i144–54. doi: 10.1093/ije/dyq03120348117 Cai Q Zhou Y Hong M Chen D Xu X. Healthcare providers' perceptions and experiences of kangaroo mother care for preterm infants in four neonatal intensive care units in China: a qualitative descriptive study. Front Public Health. (2024) 12:1419828. doi: 10.3389/fpubh.2024.141982839040865 Cho YC Gai A Diallo BA Samateh AL Lawn JE Martinez-Alvarez M . Barriers and enablers to kangaroo mother care prior to stability from perspectives of Gambian health workers: a qualitative study. Front Pediatr. (2022) 10:966904. doi: 10.3389/fped.2022.96690436090565

Edited by: Mattia Dominoni, San Matteo Hospital Foundation (IRCCS), Italy

Reviewed by: Maria João Almeida Santos, Atlântica University, Portugal

Adwoa Pokua Boakye-Yiadom, Kwame Nkrumah University of Science and Technology, Ghana