PRONE OR SUPINE BODY POSITION AND SLEEP CHARACTERISTICS IN INFANTS

Objective. To evaluate the potential relation between body position an d sleep characteristics in normal infants. Patients. Two groups of 3-m onth-old healthy infants were evaluated: 40 infants who usually slept supine, and 40 who usually slept prone. The two groups were matched fo r gender, gestational age, postnatal age, birth weight, and total reco rding time. Recording techniques. The 80 infants were studied polygrap hically during one night in the pediatric sleep laboratory. They were allowed to fall asleep in their usual sleep position, and every 3 hour s were gently turned from prone to supine, or from supine to prone. Re sults. In each group, 6 infants were excluded from the analysis, becau se they woke up after having been turned over. In both groups, no sign ificant difference was seen between the prone and the supine body posi tions for the following variables: number of sleep state changes; numb er of gross body movements; percent of rapid eye movement sleep; satur ation with oxygen, arterial blood levels; number and duration of acid esophageal reflux; rectal temperature; mean respiratory rates; water e vaporation rates from the forehead skin; and number or duration of cen tral or of obstructive apneas. In both groups of infants, prone body p osition was associated with a significant increase in sleep duration ( +16%) and in non-rapid eye movement sleep (+25%) and a significant dec rease in number of arousals (-40%) and in their duration (-43%). Concl usions. No explanation has been found for the sleep-promoting effect o f prone body positioning. The finding could be of interest to the stud y of infants' sleep quality, as well as to the potential relation betw een body positions and sudden death during sleep.