Burden of Rhesus Iso Immunization and Pregnancy Outcomes at the Kenyatta National Hospital, 2013 2019

Abstract

Introduction: The ABO and the Rh systems remain the most clinically significant blood group antigens on the red cell membranes. The pathology of rhesus isoimmunisation entails an antigen antibody reaction between the maternal Rh antibodies in a RhD-ve woman and the red blood cell membrane in a RhD+ve foetus with resultant effect on the foetus and neonate. Isoimmunization is the process of immunizing an individual with antigen derived from a similar subject, provided that the said antigen was initially absent. Though knowledge about immunity in pregnancy is ever increasing daily, there is paucity of data about the maternal and foetal outcomes of iso immunized women locally. Continued update will result in better management of pregnant women who develop Rh Iso immunization. Objective: To determine the prevalence and outcomes of rhesus iso immunization among Rh –ve pregnant women at the Kenyatta National Hospital between January 2013 and December 2019. Methodology: This was a cross sectional study conducted at the Kenyatta National Hospital among women with Rhesus negative blood group as seen between January 2013 and December 2019. Following ethical approval from the KNH-UoN ERC, a sample survey for all the records of the 216 eligible women was done and data on the sociodemographic, isoimmunization status and clinical and maternal – fetal outcomes collected. The collected data was uploaded to the SPSS version 23 software for cleaning. A total of 194 were analysed using SPSS version 24 software. Univariate analysis was done for the sociodemographic and clinical characteristics. The prevalence of iso-immunization was calculated and presented as proportions. Fishers test statistic was used to calculate the association of rhesus iso immunization with maternal (anemia, mode of delivery and miscarriage), foetal and neonatal outcomes (Hydrops Foetalis, IUFD, poor APGAR Score and admission to NICU). A p value of 0.05 was taken to be significant statistically. Results: The mean gestation (SD) at delivery was 38.94 (3.0). Among the women with rhesus negative blood group, a majority (81, 41.8%) had blood group O-ve, 65 (33.5%) had blood group A-ve, 38 (19.6%) had blood group B –ve while only 4 (2.1%) had blood group AB –ve. The prevalence of rhesus Isoimmunization was 4.0%. Four of the iso-immunized participants (50%) had a caesarian delivery compared to 129 (69.4%) of the non iso immunized participants (p, 0.226). Three (37.5%) of the participants with iso-immunization had their fetus diagnosed with hydrops fetalis compared to only 1 (0.5% in the non iso immunized group (p<0.001). Iso immunized women were more likely to deliver earlier than 38 weeks, have children with IUFD, poor APGAR score, or admitted to the NICU (p <0.001). Conclusion: Rh negative pregnancies constitute a vital facet of our obstetrics population at the KNH. The uptake of anti-D at 34 weeks is suboptimal, in line with the guidelines. There are significantly higher rates of maternal and fetal complications among women with rhesus iso immunization. Recommendations: We recommend further studies, preferably case control studies, with larger numbers of iso immunized women to better demonstrate the strength of the association between iso immunization and maternal – fetal outcomes.