Body and head position, covering of the head by bedding and risk of sudden infant death (SID).

We examined the position of the body and head, and the covering of the head by bedding on discovery in cases of sudden infant death (SID) in Lower Saxony. Between 1.1.1986 and 31.12.1992 structured, questionnaire-based interviews were carried out with parents of 140 SID victims. Control data were taken from a population-based cross-sectional study on infant sleeping position performed by the German Health Office (BGA) in autumn 1991. Of the SID cases 86.4% were discovered in the prone position [odds ratio (OR) = 7.4, 95% confidence interval (CI) = 4.3, 12.7] and 41.4% were found with the head covered. These infants were significantly older than those where the head was uncovered (p < 0.001) and covering of the head showed a significant association with a risk of SID (OR = 20.8; 95% CI = 11.5-37.6). Of the SID cases 27.9% were discovered in the face-down position. These infants were significantly younger than the infants who were discovered with the head in a side or supine position (p < 0.001). This study confirms the increased risk of SID associated with the prone position and suggests that this association could be related to the development of hypoxaemia or hypercapnia. Together with other factors such as heat stress or an infection, hypoxaemia or hypercapnia could culminate in SID if the arousal from sleep and auto-resuscitation apparently fails.