Admission Hypothermia in Very Preterm Infants and Neonatal Mortality and Morbidity

To investigate the association between body temperature at admission to neonatal intensive care and in-hospital mortality in very preterm infants, stratified by postnatal age of death. Moreover, we assessed the association between admission temperature and neonatal morbidity.

In this cohort study from 19 regions in 11 European countries, we measured body temperature at admission for infants admitted for neonatal care after very preterm birth (<32 weeks of gestation; n = 5697) who were followed to discharge or death. Associations between body temperature at admission and in-hospital mortality and neonatal morbidity were analyzed by the use of mixed effects generalized linear models. The final model adjusted for pregnancy complications, singleton or multiple pregnancy, antenatal corticosteroids, mode of delivery, gestational age, infant size and sex, and Apgar score <7 at 5 minutes.

A total of 53.4% of the cohort had a body temperature at admission less than 36.5°C, and 12.9% below 35.5°C. In the adjusted model, an admission temperature <35.5°C was associated with increased mortality at postnatal ages 1-6 days, (risk ratio 2.41; 95% CI 1.45-4.00), and 7-28 days (risk ratio 1.79; 1.15-2.78) but not after 28 days of age. We found no associations between admission temperature and neonatal morbidity.

Admission hypothermia after very preterm birth is a significant problem in Europe, associated with an increased risk of early and late neonatal death.