Meta-analysis of the four studies found that plastic wraps (polyurethane or polyethylene bag) were statistically significantly more effective than routine care in reducing heat losses in infants aged < 28 weeks’ of gestation [weighted mean difference (WMD) 0.68oC; 95% confidence interval (CI) 0.45–0.91], but there was no difference in the risk of death during hospital stay. Compared with routine care, skin-to-skin care was effective in reducing the risk of hypothermia in infants weighing between 1200 and 2199 grams [relative risk (RR) 0.09; 95% CI 0.01–0.64]. The transwarmer mattress kept infants weighing ≤1500 grams significantly warmer than routine care and reduced the incidence of hypothermia on admission to neonatal intensive care unit. Stockinette caps were not effective in reducing heat loss in infants. There was limited reporting of pre-specified secondary outcomes throughout the studies. Hyperthermia (defined as an admission temperature to a neonatal intensive care unit or within two hours of birth of >37.5º C) was reported as the most frequent adverse effect from two trials that had used wraps or bags in the delivery room.