To evaluate exclusive breastfeeding at discharge and hospital length-of-stay in preterm infants undergoing or not the Kangaroo-Mother Care Method (KMC). A retrospective cohort study was conducted including preterm infants < 1800 g admitted to the neonatal unit of a KMC reference center. The infants were grouped into the KMC group and the non-KMC group. Multiple logistic and Poisson regressions were performed to evaluate the association between the KMC and two outcomes, exclusive breastfeeding at discharge, and hospital length-of-stay, adjusted for potential confounders. 115 mother-infant dyads were included, 78 in the KMC group and 37 in the non-KMC group. In the bivariate analysis, the KMC group had a lower prevalence of maternal adverse conditions (6% vs. 32%, p < 0.001), a higher number of prenatal visits (median 6 vs. 3.5, p < 0.001), higher gestational ages (median 32 vs. 31 weeks, p < 0.05), higher birth weights (median 1530 vs. 1365 g, p < 0.01), a lower prevalence of necrotizing enterocolitis (3.8% vs. 16.2%, p < 0.05), parenteral nutrition (50% vs. 73%, p < 0.05), and deep vascular access (49.7% vs. 78.4%, p < 0.01), a higher prevalence of exclusive breastfeeding (65% vs. 8%, p < 0.001) and a shorter length of hospital stay (median 28 vs. 42 days, p < 0.001). In the multiple regression analysis, the KMC group was 23 times more likely to be exclusively breastfed at discharge (OR = 23.1; 95% CI = 4,85-109,93) and had a 19% reduction in the hospital length-of-stay (IDR = 0.81; 95% CI = 0.76-0.86) compared to the non-KMC group. The KMC is associated with better short-term neonatal outcomes and should be encouraged in all Brazilian maternity hospitals.

To describe the association of maternal and neonatal characteristics with the adherence status to the in-hospital stages of the Kangaroo-Mother Care Method - KMC (full, partial, and no-adherence). Retrospective cohort study including infants < 2500 g admitted to a reference maternity hospital for the KMC in Rio de Janeiro from January to December 2018. Maternal and neonatal characteristics were distributed according to the adherence status to the KMC in-hospital stages. In the first stage, KMC is performed in Neonatal Intensive Care Unit and Conventional Neonatal Intermediate Care Unit. The second stage is completed in Kangaroo Neonatal Intermediate Care Unit. Multinomial multiple regression was performed with KMC adherence as a three-category dependent variable and maternal and neonatal characteristics as independent variables. Of 166 dyads, 102 (61.5%) participated in two stages. Those who did not participate in any stage (n = 52; 31.3%) had a lower level of education, a higher frequency of adverse conditions, and were more often single mothers; mothers who participated only in the first stage (n = 12; 7,2%) had more premature and sick infants. Conditions associated with adherence to the two stages compared to no adherence were: high school education (OR = 2.34; 95% CI = 1.08-5.07), presence of a partner (OR = 3.82; 95% CI = 1.7-8.61), no adverse conditions (OR = 3.54; 95% CI = 1.59-7.89) and no neonatal resuscitation (OR = 2.73; 95% CI = 1.22-6.1). The study identified maternal and neonatal conditions associated with adherence status to the KMC. The results suggest opportunities to improve adherence.

Background/Objectives: Kangaroo Mother Care (KMC) has been proposed as a protective intervention that may modulate the epigenetic regulation of stress-related genes, such as SLC6A4, which encodes the serotonin transporter. Few studies have explored this association in humans. This study aimed to evaluate whether KMC affects the methylation status of SLC6A4 in preterm newborns. Methods: This longitudinal observational study included preterm infants with birth weight ≤ 1800 g and gestational age between 25 and 34 weeks. Blood samples were collected at birth, Neonatal Intensive Care Unit discharge, and hospital discharge. Methylation levels at 13 CpG sites within the SLC6A4 promoter region were quantified by bisulfite conversion and pyrosequencing. Methylation dynamics were analyzed using linear mixed-effects models adjusted for clinical covariates. Results: 75 preterm infants were analyzed (51 KMC; 24 non-KMC). Methylation levels ranged from 0.78% to 10.76% across all CpG sites and remained stable over time. At hospital discharge, the KMC group exhibited lower methylation at CpG6 than the non-KMC group (median = 0.96% vs. 1.21%, p = 0.021), but this difference was not statistically significant after correction for multiple testing. No significant differences were observed at other sites or in longitudinal methylation trajectories between groups. Conclusions: KMC was not associated with major longitudinal changes in SLC6A4 methylation during the neonatal period. The nominal difference at CpG6 should be interpreted as exploratory and warrants further investigation. Larger, multicenter studies with long-term follow-up are needed to clarify the epigenetic mechanisms linking early caregiving experiences with stress regulation and neurodevelopmental outcomes in preterm infants.