Transgenerational Transmission of Preterm Birth Risk: The Role of Race and Generational Socio-Economic Neighborhood Context.

Objectives We investigated associations of mothers' preterm birth (PTB) status with her infants' PTB risk. We also examined whether this relationship differs by mothers' race and generational socio-economic neighborhood context. Methods Participants were 6592 non-Hispanic (NH) white and NH black mother-infant pairs born in 2009-2011 and 1979-1998, respectively, in Allegheny County, Pennsylvania. Birth records were used to determine gestational age at birth, PTB status (<37 completed weeks of gestation), and PTB subgroups-late and early PTB (34-36 weeks and <34 completed weeks of gestation, respectively). Census data on tract racial composition and household income were used to characterize residential race and economic environment. Logistic regression models were used to calculate Odds Ratios (ORs), Relative Risk Ratios (RRR), and 95% confidence intervals (CIs). Stratified analyses were conducted to assess effect modification. Results Overall, 8.21, 6.63 and 1.58% infants had PTB, LPTB, and EPTB, respectively. Maternal PTB status was associated with a 46% increase in infant PTB (95% CI: 1.08-1.98), EPTB (95% CI: 0.80-2.69), and LPTB (95% CI: 1.04-2.04) risk. Maternal PTB-infant PTB associations, particularly maternal PTB-infant LPTB associations, were stronger among NH blacks, mothers in neighborhoods with a high percentage of NH black residents in both generations, or mothers who moved to neighborhoods with a higher percentage of NH black residents. Conclusions for Practice Race and generational socio-economic neighborhood context modify transgenerational transmission of PTB risk. These findings are important for identification of at-risk populations and to inform future mechanistic studies.