European Journal of Cardiovascular Medicine

Intrauterine Growth Restriction (IUGR) remains a critical public health concern, affecting approximately 10% of pregnancies worldwide and contributing significantly to neonatal morbidity and mortality [1]. Unlike infants who are merely small for gestational age (SGA) due to constitutional factors, IUGR implies a pathological restriction of genetic growth potential, often due to placental insufficiency. These infants are born with compromised glycogen stores and minimal subcutaneous fat, placing them at high risk for hypoglycemia, hypothermia, and metabolic instability [2]. Furthermore, the "brain-sparing" effect observed in fetal life—where blood flow is diverted to the brain at the expense of somatic growth—does not guarantee protection against long-term neurodevelopmental deficits. Evidence suggests that IUGR infants are prone to cognitive delays, motor deficits, and behavioral issues in later childhood [3].

In the high-technology environment of a Level III Neonatal Intensive Care Unit (NICU), the focus is often on life-sustaining interventions. However, the separation of the infant from the mother can induce physiological stress, elevate cortisol levels, and hinder neurodevelopmental organization. Kangaroo Mother Care (KMC), defined as early, continuous, and prolonged skin-to-skin contact between the mother and the baby, has been established as a high-impact, low-cost intervention for preterm infants [4]. The World Health Organization recommends KMC for the routine care of newborns weighing 2000g or less. The physiological benefits of KMC include improved thermoregulation, stabilization of heart rate and respiration, and promotion of breastfeeding [5].

Despite the extensive literature on KMC for general preterm populations, there is a relative paucity of data specifically targeting IUGR infants within Level III NICUs. IUGR infants have distinct metabolic profiles compared to appropriate-for-gestational-age (AGA) preterm infants. Their higher metabolic rate and increased caloric requirements for catch-up growth present unique challenges [6]. While some studies indicate that KMC facilitates breastfeeding, it is unclear whether the reduced energy expenditure associated with KMC translates directly into superior weight gain velocity specifically for the growth-restricted phenotype [7]. Moreover, while KMC promotes maternal-infant bonding, the extent to which it can ameliorate the specific neurodevelopmental insults caused by chronic intrauterine hypoxia remains an area of active investigation [8].

Existing research has primarily focused on mortality and severe morbidity, with fewer studies examining granular growth kinetics and early neurodevelopmental milestones using standardized tools like the Bayley Scales of Infant Development (BSID) specifically in the IUGR subset [9]. This study aims to bridge this research gap by evaluating the impact of KMC on weight gain velocity, length of hospital stay, and neurodevelopmental outcomes at 6 months corrected age in IUGR infants admitted to a Level III NICU.

Study Design and Setting: This prospective, open-label, randomized controlled trial was conducted over a period of 18 months in the Level III Neonatal Intensive Care Unit of a tertiary care university hospital. Written informed consent was obtained from the parents of all eligible infants.

Participants
The study population consisted of infants diagnosed with IUGR, defined as a birth weight below the 10th percentile for gestational age (using Fenton growth charts) combined with prenatal Doppler evidence of placental insufficiency (e.g., increased pulsatility index of the umbilical artery). Inclusion criteria comprised: gestational age between 32 and 36 weeks, hemodynamic stability (defined as stable vital signs without inotropic support), and tolerance of enteral feeds (at least 25% of total fluid requirement).

Exclusion criteria included major congenital malformations, genetic syndromes, severe perinatal asphyxia (Apgar score <3 at 5 minutes), grade III/IV intraventricular hemorrhage, or necrotizing enterocolitis (Bell’s stage II or higher).

Sample Size and Randomization: Based on previous studies indicating a standard deviation of 2.5 g/kg/day in weight gain velocity, a sample size of 52 infants per group was calculated to detect a difference of 1.5 g/kg/day with 80% power and a 5% alpha error. To account for a 15% attrition rate, 120 infants were recruited. Participants were randomly assigned using computer-generated block randomization into two groups: Group A (KMC) and Group B (Control).

Intervention

• Group A (KMC):Infants received intermittent Kangaroo Mother Care. Mothers were counseled on the technique, placing the infant prone between the breasts in an upright position, skin-to-skin, covered by a blanket. The target duration was a minimum of 6 hours per day, divided into sessions of at least 1 hour. This continued until discharge.
• Group B (Control):Infants received standard Level III NICU care, managed in incubators or under radiant warmers. Mothers were encouraged to visit and handle their babies but did not practice skin-to-skin contact for prolonged periods.

Both groups followed a standardized feeding protocol involving breast milk (fortified when indicated) or preterm formula if breast milk was unavailable.

Outcome Measures

• Primary Outcome:Weight gain velocity calculated as , where  is weight at enrollment,  is weight at discharge,  is the average weight, and  is the number of days.
• Secondary Outcomes:Length of stay (LOS), head circumference growth (cm/week), and incidence of exclusive breastfeeding at discharge.
• Neurodevelopmental Outcome:Assessed at 6 months corrected gestational age using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III), measuring Cognitive, Motor, and Language composite scores.

Statistical Analysis: Data were analyzed using SPSS software (Version 26.0). Continuous variables were checked for normality using the Shapiro-Wilk test. Descriptive statistics were presented as mean  standard deviation (SD) or frequency (%). Group comparisons for continuous variables were performed using the independent Student's t-test. Categorical variables were analyzed using the Chi-square test or Fisher's exact test. A p-value of  was considered statistically significant.

A total of 145 infants were screened, of whom 120 met the inclusion criteria and were randomized into the KMC group () and the Control group (). Five infants (2 from KMC, 3 from Control) were lost to follow-up before the 6-month assessment; however, their discharge data were included in the intention-to-treat analysis for primary outcomes.

Baseline Characteristics: The demographic and clinical characteristics at baseline were comparable between the two groups. There were no statistically significant differences regarding gestational age, birth weight, gender distribution, or maternal age (Table 1).

Table 1: Baseline Maternal and Neonatal Characteristics

Anthropometric and Clinical Outcomes
The KMC group demonstrated superior growth parameters. The daily weight gain velocity was significantly higher in the KMC group compared to controls ( vs.  g/kg/day; ). Additionally, head circumference growth, a proxy for brain growth, was significantly greater in the intervention group. The length of hospital stay was reduced by an average of 5.4 days in the KMC group (Table 2).

Table 2: Growth and Clinical Outcomes at Discharge

Neurodevelopmental Outcomes
At 6 months corrected age, 115 infants (KMC , Control ) underwent BSID-III assessment. The KMC group scored significantly higher in the Cognitive and Motor composite scales. Language scores were higher in the KMC group but did not reach statistical significance (Table 3).

Table 3: BSID-III Scores at 6 Months Corrected Age

This study highlights the efficacy of Kangaroo Mother Care in improving somatic growth and early neurodevelopment outcomes specifically in IUGR infants managed in a Level III NICU. Our findings demonstrate that KMC significantly accelerates weight gain velocity and head circumference growth while reducing the length of hospital stay. Furthermore, infants receiving KMC showed superior cognitive and motor scores at 6 months of corrected age.

The weight gain velocity observed in the KMC group ( g/kg/day) was markedly higher than in the control group. This aligns with the findings of Charpak et al., who established KMC as an effective method for thermal control and growth in general low birth weight populations [10]. The mechanism underlying this accelerated growth in IUGR infants is likely multifactorial. IUGR infants possess limited subcutaneous fat, making them prone to thermal instability. The conductive heat transfer during skin-to-skin contact reduces the metabolic cost of thermoregulation, thereby conserving calories for somatic growth [11]. This "energy sparing" is crucial for IUGR infants who require catch-up growth to mitigate long-term metabolic risks. Additionally, the significant increase in exclusive breastfeeding rates in our KMC group (80% vs. 51.7%) contributes to better weight gain, as breast milk provides optimal nutrition and bioactive factors tailored to the infant's needs [12].

Regarding neurodevelopment, the "brain-sparing" physiology of IUGR creates a vulnerability where the brain is preserved relative to the body, but often at the cost of subtle microstructural changes and reduced cortical volume. Our data showed significantly higher head circumference growth in the KMC group, which correlates with brain volume accretion [13]. The BSID-III scores at 6 months indicated improved cognitive and motor outcomes. This is consistent with recent trials suggesting that the sensory inputs provided by KMC—tactile stimulation, maternal heartbeat, and voice—promote neural organization and synapse formation [14].

Furthermore, the reduction in NICU stress is a vital component. Separation and procedural pain in Level III units elevate cortisol levels, which can be neurotoxic to the developing brain, particularly the hippocampus. KMC has been shown to attenuate the hypothalamic-pituitary-adrenal (HPA) axis response to stress, potentially protecting neurodevelopmental trajectories [15]. The higher motor scores may also reflect the improved muscle tone and motor organization observed in infants who experience containment and flexed positioning during KMC, contrasting with the varying postures in an incubator.

While language scores were higher in the KMC group, the difference was not statistically significant (). This contrasts with some literature suggesting early vocalization benefits from KMC [16]. It is possible that language differences manifest later in childhood, and a 6-month follow-up is insufficient to detect these subtleties.

The reduction in length of stay by approximately 5 days has significant economic implications for healthcare systems, particularly in resource-limited settings where NICU beds are scarce [17]. By facilitating earlier physiological stability and breastfeeding competence, KMC allows for earlier discharge without compromising safety.

Limitations: This study was limited by its single-center design and the inability to blind the intervention due to the nature of KMC. Additionally, the follow-up period of 6 months is relatively short; long-term surveillance is necessary to determine if these neurodevelopmental advantages persist into school age.

In conclusion, Kangaroo Mother Care is a potent, feasible, and cost-effective intervention for IUGR infants admitted to Level III NICUs. It offers significant advantages over standard care regarding weight gain velocity, head growth, and reduction in hospital stay. Importantly, KMC provides a neuroprotective buffer, resulting in improved cognitive and motor outcomes in early infancy. Given the specific vulnerabilities of growth-restricted infants, KMC should be integrated not merely as a humanizing measure, but as a standard therapeutic modality in their clinical management. Future research should focus on the long-term metabolic and cognitive trajectories of these infants to further validate these findings.

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