Maternal factors in the incidences of low birthweight infants among black and white mothers.

Abstract

Summary: Black mothers (1077) and white mothers (2333) were placed in one of three groups, depending on whether they had medical complications of pregnancy, one or more of seven behavioral conditions of pregnancy, or had no medical complications and no behavioral conditions. The seven behavioral conditions included 1) cigarette smoking or 2) low maternal weight gains in pregnancy, 3) being under 17 years or 4) over 35 years of age at delivery, 5) absence of any prenatal care, 6) being underweight for height at conception, and 7) use of addicting drugs or large amounts of alcohol during pregnancy. The incidences of low birth weight (LBW) infants (<2500 g) were not significantly higher in the lowest than in the highest of the socioeconomic groups of either black or white mothers when mothers were matched either for medical complications, for behavioral conditions, or for neither. The higher incidences of LBW infants in the lowest socioeconomic groups of black and of white mothers were most probably related to the higher incidences of mothers with behavioral conditions and the lower incidence of mothers who had neither medical complications nor behavioral conditions in the lowest socioeconomic groups. The incidences of LBW infants were low (1–3%) in both whites and blacks irrespective of socioeconomic status in the absence of medical complications and behavioral conditions of pregnancy. Socioeconomic status apparently had no significant effect on the incidence of medical complications of pregnancy, but was associated with an increasing incidence of mothers with behavioral conditions as socioeconomic circumstances worsened. Speculation: Data in the present study suggest that decisions women make with respect to seven specific behaviors in connection with their pregnancies are primary factors in determing the incidence of low birthweight infants and that specific social and economic factors are of secondary importance. Consideration should be given to reduce the incidence of low birthweight infants by making prospective parents aware of the importance of these seven behavioral conditions in determining pregnancy outcome for their offspring.