Racial differences in neonatal hypoglycemia among very early preterm births.

Objective: To determine whether the prevalence of neonatal hypoglycemia differs by race/ethnicity.

Study Design: A retrospective cohort study using prospectively collected data from 515 neonates born very preterm (<32 weeks) to normoglycemic women and admitted to the neonatal intensive care unit (NICU) at a major tertiary hospital in Boston, MA, between 2008 and 2012.

Results: A total of 61%, 12%, 7%, 7%, and 13% were White, Black, Hispanic, Asian, and Other, respectively. Among the 66% spontaneous preterm births, 63% of the black neonates experienced hypoglycemia (blood glucose level < 40 mg/dL), while only 22-30% of the other racial/ethnic neonates did so (Black vs. White RR 2.15; 95% CI: 1.54-3.00). After adjusting for maternal education, maternal age, multiple gestations, delivery type, gestational age, birth weight, and neonates' sex, this association remained significant (adjusted Black vs. White RR: 1.61, 95% CI: 1.13-2.29). An increased risk of infant hypoglycemia was not seen in infants of other racial/ethnic groups, nor in any racial/ethnic group with a medically indicated preterm birth.

Conclusions: Black neonates delivered for spontaneous (but not medical) indications at <32 weeks had a higher risk of hypoglycemia, which could provide critical information about mechanisms of preterm birth and adverse postnatal outcomes in this high-risk group.