African American women's lifetime upward economic mobility and preterm birth: the effect of fetal programming.

Abstract

We investigated whether African American mothers' upward economic mobility across the life course and having been of low birth weight are associated with the preterm birth of their children. We performed stratified and multilevel logistic regression analyses on an Illinois transgenerational data set of African American infants (born 1989-1991) and their mothers (n = 11 265; born 1956-1976) with appended US Census income information. African American mothers with a lifelong residence in impoverished neighborhoods had a preterm birthrate of 18.7%. African American mothers with early life impoverishment who experienced low, modest, or high upward economic mobility by adulthood had lower preterm birthrates of 16.0% (rate ratio [RR] = 0.9; 95% confidence interval [CI] = 0.8, 0.9), 15.2% (RR = 0.8; 95% CI = 0.7, 0.9), and 12.4% (RR = 0.7; 95% CI = 0.6, 0.8), respectively. In multilevel logistic regression models of former low birth weight and non-low birth weight mothers aged 20 to 35 years, the adjusted odds ratio (95% confidence interval) of preterm birth for those who experienced high upward economic mobility (vs those with lifelong impoverishment) was 0.9 (0.5-1.6) and 0.7 (0.5-0.9), respectively. African American mother's upward economic mobility from early life impoverishment is associated with a decreased risk of preterm birth. However, consistent with fetal programming, this phenomenon fails to occur among mothers born at low birth weight.