Neonatal Hypothermia at and after Admission: Burden and Associations with Outside Air Temperature and Neonatal Ward Temperature in Four Sub-Saharan African Countries Implementing with the NEST360 Alliance

Abstract

Abstract Background Annually, 2.3 million newborns die, largely from preventable causes. Neonatal hypothermia is an important contributor to morbidity and mortality, particularly in low-resource settings. This study quantified the burden of hypothermia at and after admission in four NEST360-supported countries and examined associations between outside air temperature, ward temperature, and neonatal hypothermia. Methods We conducted a retrospective analysis of newborn admissions (January 2021 to June 2025) across 66 neonatal units in Kenya, Malawi, Nigeria, and Tanzania. Hypothermia was defined using WHO thresholds (mild: 36.0–36.4°C; moderate: 32.0–35.9°C; severe: <32.0°C). Newborn admission and lowest after admission body temperatures were extracted from routine clinical records. Ward temperatures were captured using the Hadli™ Monitoring System, and environmental temperatures were obtained from Open-Meteo. Multivariate ordinal logistic regression assessed associations between air temperature, ward temperature, and hypothermia at admission and during admission. Results Among 418,458 newborn admissions with recorded admission temperatures, 47.3% (n=220,684) were hypothermic at admission (country range: 22.8%–61.9%), while 63.5% (n=48,746) experienced hypothermia during hospital stay (country range: 18.5%–74.4%), based on 76,855 admissions (July 2024–June 2025) with temperature data. Based on admission and subsequent temperature, 28.5% had no documented hypothermia, 8.6% improved to non-hypothermic status, 29.4% developed hypothermia after admission, and 33.5% experienced hypothermia at admission and during hospital stay. Across 59 neonatal units, minimum ward temperatures >26°C were maintained on 92.6% of 365 days. At admission, ward temperatures of 30–33°C were associated with 9% lower odds of a lower thermal category versus 26–28°C (p<0.01). After admission, ward temperatures of 28–30°C reduced odds by 18% (p<0.05). Warmer outside temperatures (>24°C day, >21°C night) were protective, corresponding to 19% and 68% lower odds of a lower thermal category after admission, respectively, compared with 19–24°C and 15–21°C reference groups. Newborns had 3.6-fold higher odds of hypothermia at night than during the day. Each 1°C increase in post-admission temperature reduced odds of death by 6%. Conclusion Neonatal hypothermia remains highly prevalent despite most units maintaining ward temperatures above WHO minimum standards (26°C). Strengthening all components of the warm chain, particularly at night and during colder seasons, is essential to reduce hypothermia and improve survival. Key Findings