Burden of Rhesus isoimmunization and pregnancy outcomes: a cross-sectional study conducted at Kenyatta National Hospital, Kenya.

Abstract

Introduction: the ABO and Rhesus systems remain the most clinically significant blood group antigens on red blood cell membranes. Rhesus isoimmunization occurs when maternal Rh antibodies in a RhD-negative woman react with red blood cells of an RhD-positive fetus, leading to adverse fetal and neonatal outcomes.

Methods: a cross-sectional review of 194 medical records of RhD-negative pregnant women managed at Kenyatta National Hospital (KNH) between 2013 and 2019 was conducted. Data on sociodemographic, obstetric, and clinical characteristics were extracted and analyzed using SPSS version 23. Multivariable logistic regression was performed to determine associations between Rh isoimmunization and adverse pregnancy outcomes. Adjusted odds ratios (aORs) with 95% confidence intervals were calculated, and p<0.05 was considered statistically significant.

Results: the mean age (SD) of participants was 30.1 years, and the mean gestational age at delivery was 38.9 weeks. Most participants were multigravida (69.1%) and married (91.2%). The prevalence of Rh isoimmunization was 4.1%. Isoimmunized women had significantly higher odds of miscarriage (aOR 5.64, 95% CI 1.48-21.53; p=0.01), hydrops fetalis (aOR 8.72, 95% CI 2.10-36.12; p<0.001), intrauterine foetal death (aOR 9.83, 95% CI 2.75-35.12; p<0.001), low birth weight <2500g (aOR 7.40, 95% CI 1.93-28.43; p=0.004), and poor APGAR score <7 at 5 minutes (aOR 10.26, 95% CI 2.98-35.32; p<0.001). Neonates of isoimmunized mothers were also more likely to require neonatal intensive care unit (NICU) admission (aOR 6.92, 95% CI 1.41-33.84; p=0.02).

Conclusion: the prevalence of Rh isoimmunization among RhD-negative women at KNH was 4.1%. Isoimmunization was significantly associated with miscarriage, hydrops fetalis, IUFD, low birth weight, poor APGAR scores, and NICU admission. Strengthening routine anti-D prophylaxis and improving documentation of its administration after pregnancy loss or delivery are critical to reducing isoimmunization and related complications.