Hypothermia risk factors in the very low weight newborn and associated morbidity and mortality in a neonatal care unit

Introduction: Heat loss in the newborn after delivery could interfere with post-natal adaptation due to metabolic and hemodynamic instability. Associated perinatal factors and their relationship with morbidity and mortality during the neonatal period have not been systematically studied in our unit. Objectives: To determine the temperature of very low birth weight (VLBW) infants on admission to our NICU, and to determine the associated perinatal variables, and the association of temperature with morbidity and mortality. Patients and methods: Infants born in our maternity from January 2006 to November 2012, with birth weights (BW) 401 g to 1,499g and/or less than 30 weeks gestational age, were included. A multivariate analysis was performed using the perinatal variables and the temperature on admission, as well as a logistic regression between these and the morbidity-mortality variables, in order to detect any independent associations. Results: A total of 635 infants were included, with a mean (+/- SD) birth weight and gestational age of 1,137.6 +/- 257.6 g, and 29.5 +/- 2.0 weeks, respectively. The mean admission temperature was 35.8 +/- 0.6 degrees C (range: 33.0-37.8 degrees C). The proportion of infants with a temperature <36 degrees C was 44.4%. Independently associated perinatal variables were chorioamnionitis, birth weight, vaginal delivery, and advanced cardiopulmonary resuscitation (CPR). Admission hypothermia was associated with severe intraventricular haemorrhage (IVH) (grades 3 and 4) (OR: 0.377; 95% CI: 0.221-0.643; P<.001), and mortality (OR: 0.329; 95% CI: 0.208-0.519; P=.012). Conclusions: Hypothermia on admission is frequent among our VLBW infants. Birth weight, vaginal delivery, and advanced CPR were the principal variables associated with hypothermia. A low temperature on admission was related to an increased risk of IVH and mortality. (C) 2012 Asociacion Espanola de Pediatria. Published by Elsevier Espana, S.L. All rights reserved.