Prevalence and associated factors of admission hypothermia among neonates admitted to the premature baby unit of a secondary care hospital in Sri Lanka: a cross-sectional analytical study.

Background: Hypothermia is defined as core body temperature being below 36.5°C. This study aimed to identify the prevalence, associated factors and outcomes of hypothermia among neonates admitted to the premature baby unit (PBU) of a secondary care hospital in Nawalapitiya, Sri Lanka.

Methods: In a cross-sectional analytical study, medical records of neonates admitted to the PBU were selected retrospectively from 31 March 2022 to 1 April 2021 using consecutive sampling. The recorded axillary temperatures on admission, sociodemographic and clinical data were extracted. Following bivariate analysis, multivariable logistic regression was performed.

Results: Among 407 neonates, the median admission age was 1 day. The majority were male (52.6%), were term (59%) and had a normal birth weight (52.5%). The number of babies with hypothermia was 157 with a prevalence of 38.6% (95% CI: 33.9 to 43.4). Maternal factors like teenage pregnancy, multiple pregnancy, hypertension during pregnancy, premature rupture of membranes and lower-segment caesarean sections; neonatal factors like age on admission being less than 24 hours, prematurity, corrected gestational age on admission being less than 37 weeks, low birth weight, weight on admission being less than 2.5 kg and having been resuscitated at birth had statistically significant associations with hypothermia on the bivariate analysis. Hypothermia showed no significant association with the month of admission. Following multivariable analysis, age on admission being less than 24 hours (adjusted OR (aOR): 3.3, 95% CI: 1.9 to 5.8), teenage pregnancy (aOR: 8.2, 95% CI: 1.8 to 37.2), multiple pregnancy (aOR: 2.8, 95% CI: 1.1 to 7.1) and hypertension in pregnancy (aOR: 2.3, 95% CI: 1.2 to 4.7) remained statistically significant. Neonates with hypothermia had 5.2 times (95% CI: 1.8 to 14.6) odds of mortality and 4.9 times (95% CI: 2.8 to 8.5) odds of receiving ventilatory support compared with normothermic neonates. Hypothermia also showed statistically significant associations with infant respiratory distress syndrome, metabolic acidosis and neonatal jaundice.

Conclusions: Nearly two out of five neonates admitted to the PBU were hypothermic. There were significant maternal and neonatal associations to be addressed. Hypothermia on admission may indicate serious neonatal morbidity and mortality.