Hypothermia in the newborn: An exploration of its cause, effect and prevention

Hypothermia is considered to be a major contributing factor to neonatal morbidity and, in extreme cases, mortality (Kumar et al, 2009). Newborns are at risk of hypothermia irrespective of their nationality, sex and gestation. Modern technology, advanced medical techniques and evidence-based practice contribute to reduced rates of neonatal morbidity and mortality in resource rich countries. Educated and trained health professionals decrease the risk of hypothermia in the newborn, while the development of professional guidelines promote a safer and more accurate management of neonatal hypothermia and its effects (Knobel et al, 2005; Chomba et al, 2008; Kumar et al, 2009; Sobel et al, 2010).

Every human, regardless of age, has the ability to maintain a core body temperature within a specific range in order to preserve good body function. Humans are homeotherms by nature; they produce their own temperature and maintain it within normal levels by balancing their heat loss and heat production according to their needs (Gardner et al, 2011). This ability of balancing body temperature is defined as thermoregulation. In contrast, difficulty in maintaining this balance is characterised as ineffective thermoregulation (Carpenito-Moyet, 2008). Newborn babies have a greater difficulty maintaining their body temperature than adults and children. This is seen most frequently and at the highest degree in premature babies (Kumar et al, 2009; Gardner et al, 2011). Preterm infants have a greater need for an environment with a neutral temperature due to their ineffective thermoregulation (Lunze and Hamer, 2012). Once born, the baby is exposed to an atmospheric temperature (about 25°C)—significantly below intrauterine temperature (approximately 37°C). This ‘colder’ environment, in combination with the newborn's wet body, results in a heat-loss of between 0.1°C to 0.3°C per minute and of up to of 0.2°C to 1°C per minute (where there are no precautions taken regarding neonatal thermal protection after birth) (Waldron and MacKinnon, 2007; Kumar et al, 2009). This cold-shock stimulates the newborn to commence two main physiological mechanisms in order to produce heat and to maintain its temperature at normal levels (Kumar et al, 2009).