The prone or
side sleep position can increase the risk of rebreathing expired gases, resulting in hypercapnia and hypoxia.54, — , 57 The prone position also increases the risk of overheating by decreasing the rate of heat loss and increasing body temperature compared with infants sleeping supine.58, 59 Recent evidence suggests that prone sleeping alters the autonomic control of the infant cardiovascular system
during sleep, particularly at 2 to 3 months of age, 60 and can result in decreased cerebral oxygenation.61 The prone position places infants at high risk of SIDS (odds ratio [OR]: 2.3 — 13.1).62, — , 66 However, recent
studies have demonstrated that the SIDS risks associated with
side and prone position are similar in magnitude (OR: 2.0 and 2.6, respectively) 63 and that the population - attributable risk reported for
side sleep position is higher than that for prone position.65, 67 Furthermore, the risk of SIDS is exceptionally high for infants who are placed on their
side and found on their stomach (OR: 8.7).63 The
side sleep position is inherently unstable, and the probability of an infant rolling to the prone position from the
side sleep position is significantly greater than rolling prone from the back.65, 68 Infants who are unaccustomed to the prone position and are placed prone for sleep are also at greater risk than those usually placed prone (adjusted OR: 8.7 — 45.4).63, 69,70 Therefore, it is critically important that every caregiver use the supine sleep position for every sleep
period.