Activity level of mother's usual occupation and low infant birth weight

Previous studies of the effect of mother's employment on infant birth weight have shown mixed results. This study was designed to explore the relationship between activity level of a woman's occupation and her risk of delivering a low-birth-weight infant. Using 1981 state of Washington birth certificate records, the authors selected 5,822 subjects. Case subjects were women who had delivered infants weighing 2,500 g or less; controls were those who had delivered normal-weight infants. Women were grouped into five activity levels based on their usual occupation. No association was detected between activity level of mother's usual occupation and delivery of a low-birth-weight infant. These data suggest that active work is not associated with an increased risk of having a low-birth-weight baby.