Preventing low body temperature at birth in premature and low birthweight infants may be important to survival and long-term outcome. Babies rely on external help to maintain body and skin temperature particularly in the first 12 hours of life. For vulnerable infants born prematurely or that are very small, abnormally low body temperature (hypothermia) is a world-wide issue across all climates and can lead to a variety of diseases and even death. Preventative action is taken by reducing heat loss and/or providing warmth using external heat sources. Precautionary steps routinely include a warm delivery room; drying the newborn immediately, especially the head; wrapping in pre-warmed dry blankets that cover the head; pre-warming surfaces and eliminating draughts. A review of seven studies involving 391 infants used additional preventative actions in the first 10 minutes of life to prevent problems with hypothermia. Results showed that the use of special plastic wraps or bags, plastic caps, heated mattresses and skin-to-skin contact kept the infants warmer than routine preventative action. Limitations included the small numbers of infants and studies included; variations in the methods and definitions of normal body temperature, routine care; and the use of different materials. Although this review confirmed that some of these measures are effective in preventing hypothermia, we do not yet know the long-term consequences of these interventions therefore the authors recommend that further research is carried out.
Plastic wraps or bags, plastic caps, SSC and transwarmer mattresses all keep preterm infants warmer leading to higher temperatures on admission to neonatal units and less hypothermia. However, the small numbers of infants and studies and the absence of long-term follow-up mean that firm recommendations for clinical practice cannot be given.
Keeping vulnerable preterm infants warm is problematic even when recommended routine thermal care guidelines are followed in the delivery suite.
To assess efficacy and safety of interventions designed for prevention of hypothermia in preterm and/or low birthweight infants applied within 10 minutes after birth in the delivery suite compared with routine thermal care.
We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). The review was updated in October 2009.
Trials using randomised or quasi-randomised allocations to test a specific intervention designed to prevent hypothermia, (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery suite to infants of < 37 weeks' gestational age or birthweight ≤ 2500 g.
We used the methods of the CNRG for data collection and analysis.
1) Barriers to heat loss [5 studies; plastic wrap or bag (3), plastic cap (1), stockinet cap (1)]:
Plastic wraps or bags were effective in reducing heat losses in infants < 28 weeks' gestation (4 studies, n = 223; WMD 0.68 °C; 95% CI 0.45, 0.91), but not in infants between 28 to 31 week's gestation. Plastic caps were effective in reducing heat losses in infants < 29 weeks' gestation (1 study, n = 64; MD 0.80 °C; 95% CI 0.41, 1.19). There was insufficient evidence to suggest that either plastic wraps or plastic caps reduce the risk of death within hospital stay. There was no evidence of significant differences in other clinical outcomes for either the plastic wrap/bag or the plastic cap comparisons. Stockinet caps were not effective in reducing heat losses.
2) External heat sources [2 studies; skin-to-skin (1), transwarmer mattress (1)]:
Skin-to-skin care (SSC) was shown to be effective in reducing the risk of hypothermia when compared to conventional incubator care for infants (1 study, n = 31; RR 0.09; 95% CI 0.01, 0.64). The transwarmer mattress reduced the incidence of hypothermia on admission to NICU in VLBW infants (1 study, n = 24; RR 0.30; 95% CI 0.11, 0.83).