Objective: To study traditional risk factors and the intergenerational risk factor maternal low birth weight (LBW) for respiratory distress syndrome (RDS) in infants in multiple ethnic groups.
Methods: The population-based database consists of hospital records linked to Washington state maternal and infant vital records. Four racial-ethnic groups were studied, whites, blacks, Native Americans, and Hispanics. Poisson regression models were used to estimate relative risks of various factors for RDS.
Results: Rates for RDS were whites 1.2%, blacks 1.9%, Native Americans 1.3%, and Hispanics 1.0%. Maternal LBW was associated with increased relative risk (RR) for RDS in whites (2.6, 95% confidence interval [CI] 1.6, 4.2) and blacks (3.3, 95% CI 1.9, 5.6) for infants born vaginally. Compared with mothers of normal infants, birth weights of mothers of infants with RDS and delivered vaginally were significantly lower in whites, blacks, and Native Americans. The association of maternal LBW with RDS persisted in blacks even when multiple risk factors were added to the model (RR 2.4; 95% CI 1.1, 5.1).
Conclusion: The association of maternal LBW with RDS is probably due in part to the association of maternal LBW with infant LBW and preterm birth. The strong persistent association of maternal LBW with RDS in blacks suggests that improvement of perinatal outcomes in that group will require improvement of long-term birth weight distribution.