Racial disparity in fetal growth inhibition among singletons and multiples

Objective The purpose of this study was to determine the magnitude of black-white gap in intrauterine fetal growth inhibition among singletons and multiples. Study design This was a cross-sectional study on singleton, twin, and triplet live births in the United States from 1995 through 1998. We compared the risk for low and very low-birth-weight, preterm and very preterm, and small-for-gestational age between black and white neonates. Results A total of 14,245,865 singletons (blacks = 16.2%), 392,761 twins (blacks = 18.0%), and 21,436 triplets (blacks = 7.7%) were analyzed. Black neonates depicted significantly higher risks for all indices of fetal growth inhibition regardless of plurality. The gestational age of onset of fetal growth lag for black fetuses was earliest among triplets (23 weeks and the gap remained unchanged) then singletons (26 weeks; maximum gap 37-42 weeks), and finally twins (33 weeks; maximum gap 37-40 weeks). Conclusion Black-white disparity in fetal growth inhibition varied by plurality subtypes. The different gestational ages of onset of black-white fetal growth divergence could potentially be exploited for targeting intervention measures aimed at narrowing the gap.