Aim To discover if Transwarmer® mattresses improved the thermal regulation of babies <30 weeks gestation between birth and admission to a neonatal unit.

Methods Retrospective analysis of three series: 1. Traditional drying and wrapping in a towel 2. Placement in polythene bags 3. Placement in bags and nursing on an exothermic mattress. Analysis was by intention to treat. Medians were compared with the Kruskal-Wallis test.

Results The groups were demographically similar. Admission time was longer for the “bag and mattress” than for traditional group (p<0.001) but not the “bag only” group. A greater proportion of babies in the “bag and mattress” group were hyperthermic (difference of proportions = 0.27 (0.18, 0.36) and 0.24 ((0.13, 0.34) compared to the traditional care and “bag only” groups) and their median temperature was higher (p<0.001). See table.

Conclusion Use of Transwarmer® mattresses for babies <30 weeks gestation was associated with a reduced incidence of hypothermia but an increased risk of hyperthermia on admission to the neonatal unit.