Prevalence of maternal alloantibodies in a large teaching hospital and their impact on outcomes of fetuses/neonates

Alloimmunization to Rh Antigen (D, C, E, C, E) Among Pregnant Women Attending Antenatal Care in South Western Uganda

INTRODUCTION

Maternal red cell alloimmunization to Rh antigen in pregnant women occurs when the immune system is sensitized by foreign red blood cell surface antigens, in this case fetal red blood cells, inducing an immune response. Various antigens of blood group systems may cause alloimmunization, especially the Rh, Kel, Fy, JK, and MNS systems. This study aimed to determine alloimmunization to the different frequencies of Rh antigen among pregnant women in South Western Uganda.

METHODS

A total of 1369 pregnant women consented and were recruited into a cross-sectional study during their regular antenatal visits during the period August 2020 to July 2021. Samples (4 mL) of anticoagulated and coagulated blood were obtained, and Rh blood grouping including Rh antigen and the indirect antiglobulin test (IAT) was carried out using the agglutination technology of the LISS ID-Card technique in the Ortho Biovue ID-Micro Typing System.

RESULTS

Out of 1369 participants recruited to the study, 78 (5.7%) were D-, 1291 were D+, and 134 (9.8%) had alloantibodies. Among those with alloantibodies, 115 (85.8%) were D+ and 19 (14.2%) D-. The percentage alloimmunization according to the Rh antigens was highest in e (9.72%), c (2.48%), C (2.34%) and E (0.94%) antigens. With the ABO system, alloimmunization was highest in blood group B (10.7%), followed by A (10.6%), O (9.2%) and then AB (7.1%). Alloimmunization was more prevalent in D- (24%) than in D+ participants (8.9%). Rhesus antigen e was the most prevalent antigen (99.8%), followed by c. The alloimmunization rate of 9.8% among these participants is high, and appears in both D+ and D- women. The other Rhesus antigens are seen to cause alloimmunization, with antigen e causing the highest prevalence. In conclusion, there is a need to identify antibodies and study the outcome for clinical significance, especially in D+ women, to facilitate proper pregnancy management.

Irregular erythrocyte antibodies among antenatal women and their neonatal outcome at a tertiary care hospital in Northern India

BACKGROUND

Red blood cell alloimmunisation during the pregnancy is a significant cause for neonatal mortality and morbidity. This study was planned to determine the prevalence and specificity of irregular erythrocyte antibodies in antenatal mothers and their neonatal outcome.

METHODS

In this observational study, blood grouping and red cell antibody screening of mothers were performed at first visit and after 28 weeks of gestation and positive cases were identified and followed up monthly till delivery by repeating antibody titre and middle cerebral artery-peak systolic velocity. After delivery of alloimmunised mothers, cord blood haemoglobin, bilirubin and direct antiglobulin tests (DAT) were analysed and further outcome of neonate was recorded.

RESULTS

Among 652 registered antenatal cases, 18 multigravida women were found to be alloimmunised, accounting to prevalence of 2.8%. Most common alloantibody identified was anti D (>70%) followed by anti-Le^a, anti-C, anti-Le^b, anti-E and anti-Jk^a. Only 47.7% Rh D negative women received anti-D prophylaxis during previous pregnancies or whenever indicated. DAT was positive in 56.2% of neonates. Among nine DAT positive neonates, two early neonatal deaths due to severe anaemia were observed following birth resuscitation. Four antenatal mothers required intrauterine transfusion in view of fetal anaemia while three neonates received double volume exchange transfusion and top up transfusions after birth.

CONCLUSIONS

This study emphasises importance of red cell antibody screening for all multigravida antenatal women at registration of pregnancy and additionally at 28 weeks or later in high-risk cases irrespective of RhD status.

Red blood cell alloimmunization prevalence and hemolytic disease of the fetus and newborn in Israel: A retrospective study

Hemolytic disease of the fetus and newborn (HDFN) is a severe form of anemia caused by maternal antibodies against fetal red blood cells (RBC) that can cause intrauterine and perinatal morbidity and mortality. The prevalence and specificities of alloantibodies among Israeli pregnant women and clinical outcomes for their fetuses and newborns are unknown.

STUDY DESIGN AND METHODS

A retrospective study of women who gave birth between January 1, 2011, and December 31, 2011, was performed. Data were obtained for obstetric admissions from 16 of 27 hospitals, which included results of maternal ABO, D, antibody screens, antibody identification, and requirements for intrauterine or newborn exchange transfusions.

RESULTS

Data on 90 948 women representing 70% of all births during 2011 were analyzed. Antibody screen was positive in 5245 (5.8%) women. Alloantibodies, excluding anti-D titer (<16) were identified in 900 (1.0%) women. Of 191 D- women, 75 (39.3%) had anti-D titer of 16 or greater. Other common clinically significant antibodies were anti-E (204, 23%), anti-K (145, 16%), and anti-c (97, 10.8%) alone or in antibody combinations. Multiple alloantibodies were observed in 132 of 900 (15%) of women. Severe HDFN developed in 6.8% (9/132) of these pregnancies. Seventeen fetuses and newborns (0.02% of births) including one set of twins required RBC transfusions. Two fetuses whose mothers had multiple alloantibodies received intrauterine transfusions; one of them was hydropic and died.

CONCLUSION

The prevalence of RBC alloantibodies was 1.0% among Israeli pregnant women. Transfusion was required in 0.02% of the fetuses and newborns. Severe HDFN developed in 6.8% of pregnancies with multiple maternal alloantibodies.