Lower body temperature in sleeping supine infants.

Night time rectal temperature recordings were made from 103 infants sleeping in their own home in different sleeping positions. In most cases sleeping position was verified by video monitoring throughout the night. In the period before an adult-like night time body temperature pattern appeared there was no significant effect of sleeping position upon night time body temperature, in line with previous reports. Once an adult-like night time temperature pattern appeared, infants sleeping supine reached significantly lower rectal temperatures than those sleeping prone or lateral. Babies sleeping supine moved significantly more during the night and were more likely to uncover their hands and arms. These findings suggest that supine sleepers are in a different physiological condition from those sleeping prone or lateral, which may be associated with their lower vulnerability to sudden unexpected infant death.