Sleeping Position in Preterm Infants Does Not Affect Sleep Organization† 940

The American Academy of Pediatrics recommended in 1992 that term infants and also in 1996 that asymptomatic preterm infants sleep nonprone to reduce risk for sudden infant death syndrome (SIDS). While healthy preterm infants at term age have better ventilation responses to CO₂ in prone position(Martin et al. 1997), the advantage of reduced SIDS risk was felt to be greater than a short-term clinical benefit. Three month old term infants have more total sleep time (TST), more quiet sleep (QS), and fewer arousals during prone compared to supine sleeping (Kahn et al. 1993). The increase in QS and decrease in arousals seen with prone sleeping may explain why there is an increased vulnerability for SIDS in the first 4 months of life. Last year we reported our results on 6 preterm infants who showed no effect of body position on sleep. We have expanded our study to 16 infants, studied at a PCA of 36.5±0.6 weeks. The infants (mean gestational age of 32.2±3 weeks; mean birth weight of 1733±135 g) were all recorded with videopolysomnography (VPSG) for two consecutive daytime nap periods (6 hours). VPSG was scored for TST, QS, Active Sleep (AS), and Indeterminate Sleep (IS). Arousal was defined as body movement, cry, or eye opening lasting 10-60 seconds. An arousal > 60 seconds was scored as an awakening. Indices were calculated as number of arousals or awakenings per 100 minutes. Our results(see table) showed no significant differences in sleep organization based on body position. TST and percentage of QS were similar for prone and supine. The awakening index was significantly greater for supine, supporting that supine sleeping was more interrupted and less efficient. We speculate that the increase in QS and decrease in arousals which has been reported for prone sleeping in older term infants may not appear until 1-3 months corrected age, a time when the risk for SIDS is also higher for preterm infants. If the effect of body position on sleep was the mechanism for decreased SIDS risk, nonprone sleep position before and at term conceptional age may not have the same benefit in the preterm infant and there may be some physiologic disadvantages, e.g., decreased ventilatory response to CO₂.

Table 1 No caption available.