Socioeconomic status and low birth weight: a racial comparison.

The relationships between socioeconomic status, low birth weight, births to teenagers, and inadequate prenatal care were compared among white and black infants. A cohort of 127,558 singleton births, born from 1982 to 1983 in Los Angeles County, California, was evaluated. Socioeconomic status was estimated by the 1979 median family income of the census tract of maternal residence. For both racial groups the deterioration of residential area socioeconomic status was associated with a significant increase in the percentage of high-risk teenage mothers (less than 17 years of age), in the percentage of mothers with either no, only third trimester, or unknown prenatal care, and in the percentage of low birth weight infants. The rate of increase in the percentage of low birth weight in response to the socioeconomic deterioration of residential area was similar in black and in white groups. There was, however, a racial gap of 5% low birth weight that remained constant across all income areas. At the individual level, there were marked racial differences in the relative risks imposed by one's residential median family income, age, prenatal care, and pattern of interactions.