Transfusing maternal blood to her newborn baby-irrespective of ABO mismatch

Differences in maternal-newborn ABO blood groups and risk of serious infant infection

BACKGROUND

During pregnancy, various maternal IgG antibodies are transferred to the developing fetus, some of which may protect the newborn against infection. If a mother and her fetus have different A, B or O (ABO) blood groups, then transferred maternal antibodies may plausibly protect the infant against infection.

AIM

To determine if maternal-newborn ABO blood group incongruence vs. congruence is associated with a lower risk of serious infection in the infant.

DESIGN

Retrospective population-based cohort.

METHODS

We used linked patient-level datasets for all singleton hospital livebirths from 2008 to 2022 in Ontario, Canada, with known maternal and newborn ABO blood groups. We used a dichotomous exposure state, either ABO blood group congruent (N = 114 507) or incongruent (N = 43 074). The main outcome of interest was the risk of serious infant infection within 27 days, and from 28 to 365 days, after birth. Cox proportional hazard models generated hazard ratios and 95% confidence intervals, and were adjusted for maternal age, world region of origin, residential income quintile and gestational age at birth.

RESULTS

Relative to maternal-newborn congruency, incongruent ABO blood group was associated with an adjusted hazard ratio of 0.88 (95% CI: 0.80-0.97) for serious neonatal infection within 27 days of birth, and 0.93 (95% CI: 0.90-0.96) for serious infection between 28 and 365 days after birth.

CONCLUSIONS

Maternal-newborn ABO incongruence may be associated with a lower relative risk of a serious infant infection within 27 days, and from 28 to 365 days, after birth.

HDFN Resulting from Anti-U: Alternatives to Allogeneic Intrauterine Transfusion

Hemolytic disease of the fetus and newborn (HDFN) carries significant fetal mortality risks. Although anti-D as a source of HDFN has been prevented for decades using D-specific immunoglobulin to prevent alloimmunization between fetus and mother, minor blood groups may still result in disease, with potentially disastrous consequences if left untreated. Strategies such as intrauterine transfusion, early delivery, and vigilant serologic monitoring of fetal anemia have been the standards of care for alloimmunized patients, but beyond this not much more is possible. Mothers with rare phenotypes who are alloimmunized against extremely common red blood cell antigens may find access to rare antigen-negative blood units limited. This case study presents a healthy G10P6 woman with known anti-U presenting for treatment via intrauterine transfusion in the second trimester and follows the patient through successful delivery. Difficulties in obtaining rare blood for the patient because of concomitant delivery events involving 2 patients with anti-U at the facility opened discussions about the difficulties of and alternatives to intrauterine transfusion where rare blood phenotypes are involved.