Short-term morbidity and infant mortality among infants who slept supine at 1 month of age--a follow-up report.

Following evidence that prone sleeping is causally related to sudden infant death syndrome (SIDS), intervention campaigns to avoid prone sleeping in many countries have led to a large reduction in SIDS and total infant mortality. The supine position has been recommended for healthy infants in several countries. The objective of this report was to determine how usual sleep position at 1 month relates to morbidity indicators at 1 month and 12 weeks and to SIDS and postneonatal mortality using a prospective population-based live birth cohort in Tasmania, Australia. Eligible infants were the one-fifth of Tasmanian live births at higher risk of SIDS using a perinatal score. From 1 January 1988 to 31 December 1995, 9826 (89% of eligible) infants participated in the home interview. Fifty-three eligible infants died of SIDS, 51 (96%) with hospital interview data and 35 (81% of those eligible for home visit) with home visit data. The main outcome measures were SIDS, postneonatal mortality and parentally reported infant morbidity. The postneonatal mortality rates (cases per 1000 live births) by usual sleep position at 1 month of age were supine 1.60 [95% CI 0.04, 8.87], side 2.87 [1.79, 4.35], prone 10.27 [5.62, 17.18] and other (including no usual position) 6.37 [0.16, 34.98]. None of the study infants who slept supine died of SIDS at a later time. Of 25 morbidity indicators studied, only noisy breathing was increased for supine compared with side-sleeping babies. In this study, there was no evidence to suggest that supine sleeping at 1 month of age was associated with an increase in important short-term morbidity or postneonatal mortality. These findings provide further support for the recent recommendations of the American Academy of Pediatrics that healthy infants should preferably sleep in the supine position.