Trends in maternal and infant health factors associated with low infant birth weight, United States, 1972 and 1980.

Today, low birth weight--weight less than 2,500 grams (5 pounds 8 ounces)--is recognized as the single most significant characteristic of the newborn associated with a greater risk of mortality and morbidity. This paper highlights maternal and infant health factors associated with low birth weight, using data from the 1972 and 1980 National Natality Surveys. Both surveys provide important information related to low birth weight that is not typically available from standard birth certificates and therefore not part of the usual natality vital statistics. In addition, induction of labor and cesarean section deliveries (first and repeat cesareans) were examined for 1980 to assess whether their use has exerted an influence on low birth weight.