Decreased survival in necrotizing enterocolitis is significantly associated with neonatal and maternal blood group: the AB isoagglutinin hypothesis.

Objective: To determine the effect of neonatal and maternal blood group on the mortality risk from necrotizing enterocolitis (NEC).

Study Design: Retrospective chart review of all neonates admitted to the neonatal intensive care unit over 24 years. Data on birth date, gestational age, maternal/neonatal blood group, number of transfusions, and survival time (defined as date of birth to date of death/discharge) were collected on those with NEC.

Result: 276 neonates with Bell stage II-III NEC were analyzed. AB neonates had a significantly higher risk of mortality from NEC compared with other blood groups (HR 2.87; 95% CI 1.40 to 5.89; P=0.003). Multivariate analysis showed AB blood group to be an independent risk factor for mortality from NEC.

Conclusion: Neonatal and maternal blood groups are significantly associated with a neonate's survival from NEC. The increased mortality of AB neonates may be related to factors such as neonatal blood group antigens and/or transplacental transfer of isoagglutinins.