Hypothermia in very low birth weight infants: distribution, risk factors and outcomes.

The objective of this study was to study the epidemiology of neonatal hypothermia in preterm infants using World Health Organization (WHO) temperature criteria. A population-based cohort of 8782 very low birth weight (VLBW) infants born in California neonatal intensive care units in 2006 and 2007. Associations between admission hypothermia and maternal and neonatal characteristics and outcomes were determined using logistic regression. In all, 56.2% of infants were hypothermic. Low birth weight, cesarean delivery and a low Apgar score were associated with hypothermia. Spontaneous labor, prolonged rupture of membranes and antenatal steroid administration were associated with decreased risk of hypothermia. Moderate hypothermia was associated with higher risk of intraventricular hemorrhage (IVH). Moderate and severe hypothermic conditions were associated with risk of death. Hypothermia by WHO criteria is prevalent in VLBW infants and is associated with IVH and mortality. Use of WHO criteria could guide the need for quality improvement projects targeted toward the most vulnerable infants.