Social Class, Social Mobility, and Prematurity: A Test of the Childhood Environment Hypothesis for Negro Women

The purpose of this research was to explore for American Negroes the hypothesis that poverty in childhood increases the likelihood of a woman giving birth to low birth weight infants. Samples of middle-and lower-class women from a population consisting of all Negro women living in the District of Columbia terminating a pregnancy with a live birth between July 1, 1965, and June 30, 1966, were interviewed during a six-month period ending May 1, 1967, yielding a total of 1404 cases. The present analysis reports results from women currently married with husband present. Rates of premature birth did not significantly differ between mothers from lower-class backgrounds and mothers from middle class background. Neither did they differ by present class status, derived from husbands' occupation. However, women moving up out of the lower class have a significantly lower prematurity rate than women moving down out of the middle class. It seemed unreasonable to attribute the poor outcomes of the downwardly mobile to lack of food and excessive exposure to infectious disease or other environmental deficiencies during a middle-class childhood. A process of selection for mobility on a characteristic genetically related to prematurity appeared consistent with the data. The significance of environment in childhood (or other times) is questioned as an explanation for the persistent class and race differences in birth weight.