Objectives The Kangaroo method helps promote maternal breastfeeding and adequate growth of low birthweight preterm infants. The objective of this study was to analyze the association between weight-gain velocity during use of the Kangaroo method and maternal and infant variables. Methods A nested cross-sectional study in a cohort of newborn infants managed using the Kangaroo method was carried out at a reference center for the method in Brazil. Data on low birthweight and preterm infants managed using the Kangaroo Method (n = 78) and on their respective mothers (n = 70) was collected between January and July 2014. Maternal and infant variables were associated and correlated with weight-gain velocity (g/kg/day) at each phase of the method (p < 0.05). Results Mean weight-gain velocity increased from 0.12 ± 11.11 g/kg/day in the first phase to 13.47 ± 4.84 g/kg/day in the third phase (p < 0.001), and percentage of adequate weight increased at phase 3 (p < 0.001). Birthweight was inversely correlated with weight-gain velocity at phases 1 and 2 of the Kangaroo method. Birthweight of under 1500 g was associated with a lower likelihood of inadequate weight-gain velocity of the newborn at phase 1 (OR = 0.1; 95 % CI 0.01-0.78; p = 0.012). In phase 3, maternal age was directly correlated with weight-gain velocity. Conclusions Weight-gain velocity was associated with maternal (age) and infant (gestational age at birth, birthweight, weight for gestational age at birth, length of hospital stay and five-minute Apgar score) variables. Knowledge of the factors influencing weight-gain velocity and its behavior at each phase of the method can help guide conduct toward potentializing factors that promote adequate weight-gain.
Keywords: Growth; Kangaroo-mother care method; Neonatology; Newborn; Weight gain.