Prevention of RhD alloimmunization in RhD negative women

Prevalence and determinants of RH alloimmunization in Rh-negative women in teaching hospitals of Addis Ababa, Ethiopia: a hospital-based cross-sectional study

Background

Despite the implementation of immunization with an anti-D antigen for pregnant women, adverse pregnancy outcomes continue to occur in Ethiopia and most Sub-Saharan African countries. Consequently, the woman's obstetric care is compromised, and there is an increase in perinatal morbidity and mortality. In Ethiopia, the burden of the disease is not well understood, and no research has been conducted in the study area. Therefore, this study aims to determine the prevalence and determinants of Rh alloimmunization in Rh-negative women receiving care at Addis Ababa teaching hospitals.

Methods

An institutional-based cross-sectional study was conducted from 5 October 2020 to 5 May 2021, among 328 Rh-negative pregnant women who received antenatal care and delivery services at Teaching Hospitals under Addis Ababa University. Face-to-face interviews were used to gather data using a pre-tested structured questionnaire, and a chart review was performed using a checklist. The data were entered into Epidata version 3.1 and analyzed using SPSS version 22. Multivariable analysis and logistic regression were used to evaluate the predictors, and the results were presented as an adjusted odds ratio (AOR) with a 95% confidence interval. Statistical significance was declared at a p-value < 0.05.

Results

Among Rh-D negative individuals, 56(17.1%) were alloimunized with 95% CI (15.1%, 19.23%). The prevalence of Rh-D negative was 2.1% with 95% CI (1.56%, 2.76%). Factors such as unemployment [AOR = 2.28, 95% CI: 1.21, 4.28], failure to use anti-D prophylaxis in previous pregnancy [AOR = 2.08, 95% CI: 1.10, 3.92), and the presence of sensitizing events [AOR = 0.52, 95% CI: 0.27, 0.84] were statistically significant with the outcome variables.

Conclusions

This study pointed out that the prevalence of Rh was relatively large and that almost one in every five pregnant women was alloimunized. Factors such as unemployment and failure to use anti-D prophylaxis in a previous pregnancy were found to be associated with outcome variables. Therefore, all stakeholders and concerned entities should prioritize enhancing access and affordability to anti-D prophylaxis to prevent the occurrence of Rh alloimmunization and its associated adverse outcomes.

Anti-D Antibodies in Pregnant D Variant Antigen Carriers Initially Typed as RhD

BACKGROUND

To evaluate the incidence, the consequences, and the prevention strategy of anti-D alloimmunizations of D variant carriers in the obstetric population of Split-Dalmatia County, Croatia.

METHODS

RhD immunization events were evaluated retrospectively for the period between 1993 and 2012. Women were tested for RhD antigen and irregular antibodies. Those with anti-D antibody who were not serologically D- were genotyped for RHD. They were evaluated for their obstetric and transfusion history and their titer of anti-D. The neonates were evaluated for RhD status, direct antiglobulin test (DAT), hemoglobin and bilirubin levels, transfusion therapy as well as phototherapy and outcome.

RESULTS

Out of 104,884 live births 102,982 women were tested for RhD antigen. Anti-D immunization occurred in 184 women which accounts for 0.9% of individuals at risk of anti-D formation. 181 cases occurred in women serologically typed as D-. Three women were partial D carriers (DVa n = 2, DNB n = 1), initially typed RhD+, and recognized as D variant carriers after the immunization occurred. Anti-D titer varied from 1:1 to 1:16. Six children were RhD+, four had positive DAT, and two underwent phototherapy.

CONCLUSION

Anti-D immunization occurred in pregnant partial D carriers (DVa, DNB). RhD+ children had serologic markers of hemolytic disease of the fetus and newborn (HDFN), with no cases of severe HDFN.

Rhesus Negative Woman Transfused With Rhesus Positive Blood: Subsequent Normal Pregnancy Without Anti D production

Clinicians sometimes are confronted with the challenge of transfusing haemorrhaging Rhesus (Rh) D negative patients with Rh D positive blood to save their lives. There are concerns about alloimmunization and future haemolytic disease of the newborn in women of the reproductive age. Another fear is transfusion reaction if they receive another Rh D positive blood in future. We present a 32-year-old Rh D negative woman, who had postpartum haemorrhage in her first pregnancy and was transfused with Rh D positive blood because of unavailability of Rh D negative blood. She did not receive anti D immunoglobin but subsequently had a normal term pregnancy of an Rh positive fetus without any detectable anti D antibodies throughout the pregnancy. In life threatening situations from obstetric haemorrhage, transfusion of Rh D negative women with Rh D positive blood should be considered as the last resort.

Occurrence of anti-D alloantibodies among pregnant women in Kasese District, Western Uganda

OBJECTIVES

This study was undertaken to determine the distribution of ABO/RhD (rhesus D antigen) blood phenotypes, prevalence of anti-D alloantibodies, and the risk factors for alloimmunization among pregnant women in Kasese District, Western Uganda.

MATERIALS AND METHODS

Ethylenediamine tetraacetic acid-containing plasma samples and serum samples were taken from pregnant women attending the antenatal clinic. The blood groups were identified using the microplate grouping method, while the presence of anti-D alloantibodies was detected by the indirect antiglobulin test (IAT). Data were also collected from the pregnant women on the risk factors associated with anti-D alloantibody formation.

RESULTS

Among the 726 participants, the blood group distribution was as follows: O: 356 (49.%); A: 190 (26.%); B: 152 (21%); and AB: 28 (4%). A total of 28 (3.86%) pregnant women were RhD negative. Anti-D alloantibodies were detected in 88 (12.1%) of the participants; and of these, 13 (14.8%) were RhD negative. Statistically significant risk factors for anti-D alloimmunization included miscarriage, stillbirth, and postpartum hemorrhage.

CONCLUSION

Blood group O was the most common among the pregnant women in this study and the prevalence of Rh negativity was 3.8%. The frequency of anti-D alloimmunization among pregnant women in Kasese District was 12.12%, with 85.5% of these being RhD positive. Risk factors such as a history of stillbirths, miscarriages, and incidence of postpartum hemorrhage were significantly associated with anti-D alloimmunization. There is a need to routinely carry out antenatal blood grouping and IAT screening on pregnant women in Uganda to detect anti-D alloimmunization. Given the high prevalence of anti-D alloantibody formation among RhD-positive women, we recommend additional research studies on the role of autoimmunity among antigen-positive women, as well as the occurrence of RhD variants plus their implications on hemolytic disease of the fetus and newborn, in Uganda.

Assessment of feto-maternal hemorrhage among rhesus D negative pregnant mothers using the kleihauer-betke test (KBT) and flow cytometry (FCM) in Addis Ababa, Ethiopia

BACKGROUND

This study aimed to assess fetomaternal hemorrhage (FMH) among RhD negative pregnant mothers using two techniques, Kleihauer-Betke (KBT) and Flow cytometry (FCM). To determine if patient-specific doses of prophylactic anti-D warrant further investigation in Ethiopia and wider Africa.

METHODS

Hospital- based cross-sectional study was conducted among 75 RhD negative pregnant mothers using convenient sampling technique.

RESULT

FMH has been detected in 52% and 60% by KBT and FCM techniques, respectively. The volume of FMH quantified in the majority of the cases (92.5% and 87%) was <10 mL fetal blood while >30 mL in 1.3% (1/75) and 2.7% (2/75) as calculated by KBT and FCM, respectively. The FMH calculated by the two methods have good correlation; r = 0.828 (p = 0.000) for categorized and r = 0.897 (p = 0.000) for continuous values and the agreement between the FCM and KBT was moderate with kappa (κ) value of 0.53 (p = 0.000).

CONCLUSION

Most of FMH calculated (<10 mL) could have been neutralized by lower doses which might have lower costs than administering 300 μg dose which is currently in practice in our country for affording mothers. Besides, it also showed that the volume of FMH was >30 mL in 1.3% and 2.7% of the cases as calculated by KBT and FCM, respectively, which need more than 300 μg dose RhIG for neutralization. Further investigation into the cost- effectiveness and scalability of patient- specific dosing of prophylactic anti-D appears warranted.

Anti-D administration after spontaneous miscarriage for preventing Rhesus alloimmunisation

BACKGROUND

During pregnancy, a Rhesus-negative (Rh-negative) woman may develop antibodies if her fetus is Rh-positive, which can cause fetal morbidity or mortality in following pregnancies, if untreated.

OBJECTIVES

To assess the effects of administering anti-D immunoglobulin (Ig) after spontaneous miscarriage in a Rh-negative woman, with no anti-D antibodies.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 December 2012).

SELECTION CRITERIA

Randomised controlled trials (RCT) in Rh-negative women without antibodies who were given anti-D Ig following spontaneous miscarriage compared with no treatment or placebo treatment following spontaneous miscarriage as control.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and trial quality. Two review authors extracted data and checked it for accuracy.

MAIN RESULTS

We included one RCT, involving 48 women who had a miscarriage between eight to 24 weeks of gestation. Of the 19 women in the treatment group, 14 had therapeutic dilatation & curettage (D&C) and five had spontaneous miscarriage; of the 29 women in the control group, 25 had therapeutic D&C and four had spontaneous miscarriage. The treatment group received 300 µg anti-D Ig intramuscular injection and were compared with a control group who received 1 cc homogenous gamma globulin placebo.This review's primary outcomes (development of a positive Kleihauer Betke test (a test that detects fetal cells in the maternal blood; and development of RhD alloimmunisation in a subsequent pregnancy) were not reported in the included study.Similarly, none of the review's secondary outcomes were reported in the included study: the need for increased surveillance for suspected fetal blood sampling and fetal transfusions in subsequent pregnancies, neonatal morbidity such as neonatal anaemia, jaundice, bilirubin encephalopathy, erythroblastosis, prematurity, hypoglycaemia (low blood sugar) in subsequent pregnancies, maternal adverse events of anti-D administration including anaphylactic reaction and blood-borne infections.The included study did report subsequent Rh-positive pregnancies in three women in the treatment group and six women in the control group. However, due to the small sample size, the study failed to show any difference in maternal sensitisation or development of Rh alloimmunisation in the subsequent pregnancies.

AUTHORS' CONCLUSIONS

There are insufficient data available to evaluate the practice of anti-D administration in an unsensitised Rh-negative mother after spontaneous miscarriage. Thus, until high-quality evidence becomes available, the practice of anti-D Immunoglobulin prophylaxis after spontaneous miscarriage for preventing Rh alloimmunisation cannot be generalised and should be based on the standard practice guidelines of each country.