Racial Differences In Gestational Age At Delivery In A Transgenerational Preterm Birth Cohort

Delivery gestational age may be mediated by genetic factors; racial disparities in PTB rates exist between non-Hispanic (NH) black and NH white women. The impact of race on (a) subsequent deliveries among women who were born preterm and (b) the distribution of delivery gestational age are poorly defined; the objective of this study was to examine these outcomes. This was a population-based retrospective cohort using the Virginia Intergenerational Linked Birth File. All NH black and NH white women born in Virginia between 1960-1996 who delivered their first live-born, non-anomalous, singleton ≥ 20 weeks gestation 2005-2008 were included. We compared gestational age distribution of NH white and black women, followed by the gestational age distribution of their offspring. We assessed the overall gestational age distribution and gestational age stratified by preterm (<37) and term (≥37). Data were analyzed by Cox regression and Kaplan-Meier survivor functions. 71,676 mother-infant pairs [21,467 (30.0%) NH black] met inclusion criteria. 2,043 (9.5%) NH black women and 2,321 (4.6%) NH white women were born preterm, p <0.001. NH black offspring were also more likely to be preterm compared to NH white offspring [2482 (11.6%) vs. 4312 (8.6%), p<0.001]. In all comparisons, NH black race was associated with an earlier delivery gestational age compared to NH white race; this difference persisted when the analysis was limited to those born preterm, those born at term, and in both generations (Table). Kaplan-Meier survival analysis demonstrated that the earlier delivery gestational age among NH blacks was constant across gestational ages; differences in gestational age distribution were most pronounced among offspring delivered preterm <37 weeks (Figure). In a cohort of formerly preterm mothers delivering their first live-born infant, a larger proportion than expected are NH black compared to NH white race. NH black offspring had a shifted, earlier delivery gestational age compared to NH whites overall and when stratified by preterm and term delivery. Future studies should elucidate whether this gestational age difference among NH black women is physiological or pathological.View Large Image Figure ViewerDownload Hi-res image Download (PPT)