Prevalence of Rhesus D-negative blood type and the challenges of Rhesus D immunoprophylaxis among obstetric population in Ogbomoso, Southwestern Nigeria

Background: Rhesus incompatibility could pose a major problem in pregnancy, and it could be the cause of obstetric failure in a handful of women. Implementation of programs for antenatal and postnatal (Rhesus D) RhD immune globulin prophylaxis has led to a significant reduction in the frequency of maternal RhD alloimmunization and associated fetal and neonatal complications. Aims: To determine the prevalence of RhD negative among the pregnant population attending the antenatal clinic of a young tertiary health institution in Ogbomoso, a semi-urban town in southwestern Nigeria, and also the challenges faced by this sub-population of pregnant women. Materials and Methods: A retrospective review of the antenatal and labour records of obstetric patient attending Ladoke Akintola University of Technology Teaching Hospital (LTH), Ogbomoso, Nigeria. Variables were expressed as percentages. Result: Of the 596 booked patient who had their blood group systems determined, 563 women (94.5%) were RhD-positive, and 33(5.5%) women were RhD-negative. Almost 50% of the Rh-negative pregnant women were primipara. Twenty-three (69.7%) of the study population had a previous delivery or abortion, but only 9 (39.1%) of these had the Rhesus anti-D immunoglobulin following the delivery or the abortion. One of the RhD-negative women had been sensitized to the RhD positive antigen from the previous delivery at the time of booking the index pregnancy. Of the study population that delivered in our facility, only 11 (33.3 %) received the anti-D immunoglobulin after the delivery, and financial inability to purchase the anti-D immunoglobulin was a major reason for refusing the immunoprophylaxis. Conclusion: Although the prevalence of RhD negative still remains low, and the rate of Rh-immunoprophylaxis remains quite low in our obstetric population, the risk of haemolytic disease of the newborn with its attendant perinatal morbidity and mortality is real in our community. The anti-D immunoglobulin should be made available and affordable.