Neonatal Admission Temperature in Middle- and High-Income Countries

Despite being preventable, neonatal hypothermia remains common. We hypothesized that the proportion of newborns with hypothermia on admission would be high in all settings, higher in hospitals in middle-income countries (MIC) compared with high-income countries (HIC), and associated with morbidity and mortality.

Using the Vermont Oxford Network database of newborns with birth weights 401 to 1500 g or 22 to 29 weeks' gestational age from 2018 to 2021, we analyzed maternal and infant characteristics, delivery room management, and outcomes by temperature within 1 hour of admission to the NICU in 12 MICs and 22 HICs.

Among 201 046 newborns, hypothermia was more common in MIC hospitals (64.0%) compared with HIC hospitals (28.6%). Lower birth weight, small for gestational age status, and prolonged resuscitation were perinatal risk factors for hypothermia. The mortality was doubled for hypothermic compared with euthermic newborns in MICs (24.7% and 15.4%) and HICs (12.7% and 7.6%) hospitals. After adjusting for confounders, the relative risk of death among hypothermic newborns compared with euthermic newborns was 1.21 (95% confidence interval 1.09-1.33) in MICs and 1.26 (95% confidence interval 1.21-1.31) in HICs. Every 1°C increase in admission temperature was associated with a 9% and 10% decrease in mortality risk in MICs and HICs, respectively.

In this large sample of newborns across MICs and HICs, hypothermia remains common and is strongly associated with mortality. The profound burden of hypothermia presents an opportunity for strategies to improve outcomes and achieve the neonatal 2030 Sustainable Development Goal.