Low-birth-weight effects of demographic and socioeconomic variables and prenatal care in Pima County, Arizona.

Low birth weight is the major determinant of infant mortality. Continuing declines in infant mortality in the United States are due to the use of neonatal intensive care services; less progress has been made toward preventing low birth weight. I examined how the demographic, socioeconomic, and health services use variables affected rates of low birth weights in Pima County, Arizona, in 1985. Women at greatest risk of having the smallest infants were those younger than 21 years and those with fewer than 6 prenatal visits. Nulliparous women with fewer than 6 prenatal visits showed a still greater risk of having an infant of low birth weight. Women without medical insurance coverage had babies with the lowest mean birth weights, as well as significantly fewer prenatal visits. As the number of uninsured in the United States increases, the effect of lack of insurance among pregnant women becomes increasingly important. To prevent low-weight births, comprehensive maternity care services must be available to all pregnant women regardless of ability to pay.