Hypothermia in Preterm Infants in the First Hours after Birth: Occurrence, Course and Risk Factors

BACKGROUND: Hypothermia is associated with increased morbidity and mortality rates. Preterm infants frequently have hypothermia when they are admitted to the NICU, but there is no data on the occurrence of hypothermia during the first hours after admission.

OBJECTIVE: To investigate the occurrence of hypothermia in preterm infants in the first three hours of admission and to identify risk factors.

METHODS: Infants < 32 weeks of gestation included in a randomized trial with admission temperature as primary outcome were retrospectively analyzed for the occurrence of hypothermia (< 36.5°C) in the first three hours after admission. Risk factors were identified using linear regression analysis and logistic regression.

RESULTS: In total 80 infants were included with a median (IQR) gestational age at birth of 29 (27-30) weeks. In 93% of the infants hypothermia occurred in the first three hours after admission. The median (IQR) duration of hypothermia was 101 (34-162) minutes, of which 24 (7-52) minutes the hypothermia was mild, 45 (4-111) minutes moderate, severe hypothermia hardly occurred. Gestational age and the occurrence of hypothermia at birth were independent risk factors for the occurrence of moderate and severe hypothermia and significantly correlated with duration of hypothermia.

CONCLUSIONS: Hypothermia occurred often and for a long period in preterm infants in the first three hours of life, low gestational age and admission temperature were independent risk factors.