Clinical Utility of Routine Umbilical Cord Blood Screening for ABO Incompatibility: A Single-Center Observational Study

BACKGROUND: The American Academy of Pediatrics suggests 2 approaches for neonates born to blood group O mothers: routine cord blood type and Coombs testing or clinical surveillance with selective testing for jaundiced neonates. OBJECTIVE: To determine whether routine cord blood testing reduces neonatal intensive care unit (NICU) admissions for hyperbilirubinemia because of ABO incompatibility. STUDY DESIGN: This retrospective pre-post study analyzed all births at one urban, university-affiliated hospital in Pennsylvania from 2007 to 2020. The hospital transitioned from routine cord blood evaluation (2007-2012, period A) to selective evaluation (2013-2020, period B). The primary outcome was transfer from the well baby nursery (WBN) to the NICU for severe hyperbilirubinemia because of ABO incompatibility. Secondary outcomes included peak bilirubin at or above exchange threshold and intravenous immunoglobulin (IVIG) treatment. Chi-square or Fisher exact tests were used to compare differences in outcomes as a percentage of all births across the 2 time periods. RESULTS: Of 29 207 births (12 291 in period A; 16 916 in period B), a total of 1581 neonates were transferred to the NICU from WBN (5.2% in period A vs 5.5% in period B; P = .19). Transfer for hyperbilirubinemia because of ABO incompatibility was more frequent in period B than A (0.11% vs 0.03%; P = .01). During period B, more infants had bilirubin at or above exchange transfusion level (0.06% vs 0.01%; P = .02) and received IVIG (0.06% vs 0%; P = .002). CONCLUSION: For infants born to blood group O mothers, routine cord blood evaluation vs selective evaluation may prevent severe hyperbilirubinemia requiring NICU transfer.