Neonatal mortality by the day of the week in the 1974-75 Arkansas live birth cohort.

This study is an analysis of daily variations in neonatal mortality among 66,049 live births in the 1974-75 Arkansas live birth cohort. Weekends and holidays in general, and Sundays in particular, were found to have the fewest number of deliveries. Variations in deliveries by the day of the week were attributed to obstetric practices. Births weighing less than 2500 gms. were over-represented among weekend deliveries as were infants experiencing a birth-related injury. Neonatal mortality was found to be higher among weekend deliveries with a Sunday rate that was 27 per cent above the weekly average. Separate analysis by race and birth weight revealed the weekend peak to be more pronounced among non-whites. Analysis of daily variations by cause of death showed that Sundays exceeded the overall average for seven of the eight cause of death categories examined. (Am J Public Health 1981;71:601-605.)