Patterns of birth weight in relation to gestational age, maternal age, parity, and prenatal care in Texas' triethnic population, 1984 through 1986.

This study investigated the distribution of birth weights in Texas' triethnic populations for the years 1984 through 1986 (more than 900,000 births) with regard to gestational age, maternal age, parity, and visits for prenatal care. African-American infants had a systematic tendency to be born earlier and smaller than Anglo and Hispanic infants. Among the maternal age categories, mothers younger than 18 years had the highest rates of preterm birth (less than 37 completed weeks), very low birth weight (less than 1500 g), and low birth weight (less than 2500 g). High multiparity and inadequate visits for prenatal care were associated with increased rates for the same adverse pregnancy outcomes, and the risks were always much higher in African-American than in Anglo and Hispanic women of the same age, parity, and prenatal care categories. The predictive values of these associations for individual pregnancies were limited, but their recognition may improve the planning of prenatal care for Texas women and of the anticipatory care for their infants.