Original Investigation
Pediatrics
October 30, 2024
Maternal-Newborn ABO Blood Groups and Risk of Bacterial Infection in Newborns
Emily Ana Butler, Joel G. Ray, Eyal Cohen
JAMA Netw Open. 2024;7(10):e2442227. doi:10.1001/jamanetworkopen.2024.42227
Question If a mother and newborn have incongruent ABO blood groups, is the newborn at a lower risk of bacterial infection than if they had congruent ABO blood group?
Findings In this cohort study of 138 207 mother-newborn pairs, ABO blood group incongruence was not associated with a lower risk of bacterial infection within 30 days of birth.
Meaning Findings of this study suggest ABO blood group incongruence is not associated with a lower risk of bacterial infection within 30 days of birth.
Abstract
Importance Newborn immunity largely relies on maternal-fetal transfer of antibodies in utero. Incongruency in ABO blood groups between a mother and newborn may be associated with protection against serious infections, but data specific to newborn bacterial infections are lacking.
Objective To ascertain the association between maternal-newborn ABO blood group incongruence and lower risk of bacterial infection in newborns.
Design, Setting, and Participants This cohort study used linked patient-level datasets for all singleton live births between January 1, 2014, and December 31, 2020, in hospitals and health centers in Ontario, Canada. The cohort comprised maternal-newborn pairs with known ABO blood groups. Data analysis was conducted between February and May 2024.
Exposure Maternal-newborn ABO blood group incongruence vs congruence.
Main Outcomes and Measures The primary outcome was a bacterial infection arising in newborns within 30 days of birth. Bacterial infection was cultured from either blood, cerebrospinal fluid, urine, or lung specimen. Secondary outcomes were a bacterial infection with 7 days and 90 days of birth. Modified Poisson regression generated adjusted relative risks (ARRs) and 95% CIs, adjusted for neonatal sex and preterm birth.
Results A total of 138 207 maternal-newborn pairs (maternal mean [SD] age, 31.8 [5.1] years among those with ABO blood group incongruency and 31.5 [5.1] years among those with ABO blood group congruency; newborn mean [SD] gestational age, 38.5 [2.3] weeks among those with incongruency and 38.4 [2.5] weeks among those with congruency; 19 475 males [51.3%] with incongruency and 52 041 males [51.9%] with congruency) were analyzed. Of these pairs, 37 953 (27.5%) had ABO blood group incongruency and 100 254 (72.5%) had ABO blood group congruency. Within 30 days of birth, 328 (8.6 per 1000) newborns in the incongruent group and 1029 (10.3 per 1000) newborns in the congruent group experienced a bacterial infection, corresponding to an ARR of 0.91 (95% CI, 0.81-1.03). The ARRs for bacterial infection within 7 days and 90 days of birth were 0.89 (95% CI, 0.73-1.09) and 0.86 (95% CI, 0.78-0.94), respectively.
Conclusions and Relevance This cohort study found no association between maternal-newborn ABO blood group incongruence and risk of bacterial infection in newborns within 30 and 7 days of birth. However, incongruence was associated with a decreased risk of bacterial infection within 90 days of birth.
