Temporal Association Between Interracial Couples and Odds of Low Birth Weight Infants: Trends in National Vital Statistics Data from 1971 to 2016.

Our study explores the temporal association between low birth weight (LBW) infants and the increasing population prevalence of interracial relationships. Our hypothesis was that the odds of LBW would decrease as the population prevalence of interracial relationships increased. National Center for Health Statistics Natality data for 1971-2016 was analyzed. LBW was defined as birth weight less than 2500 gm. We restricted our analyses to singleton births by White and Black mothers with reported White or Black partners of the neonate. Logistic regression was used to calculate the odds ratios of LBW, both unadjusted and adjusted for maternal education and parental ages. The proportion of couples coded as interracial increased annually from 0.36% in 1971 to 3.86% in 2016 for White mothers and 0.59% to 8.63% for Black mothers during the same period. In each year the odds ratio of LBW was significant. As the proportion of White mothers with Black partners increased, their odds of LBW declined (OR1.75 to 1.30, p < 0.001). The odds ratio of LBW among Black mothers with White partners did not change and remained stable between 0.70 and 0.80 (p = 0.22) over the same time period. As the annual proportion of White mothers with Black partners increased, their odds of LBW decreased when compared to White couples. Black mothers with White partners did not exhibit a similar change when compared to Black couples, with the odds ratio of LBW remaining stable.