Abnormal haemoglobin variants, ABO and rhesus blood group distribution among pregnant women in a secondary health centre in Ibadan, South-West.uth West Nigeri

Abstract

Abstract Background: The distribution of the ABO and Rh and abnormal haemoglobin variants will determine the blood type and slock levels in hospital blood banks. This study determined the prevalence of haemoglobin variants, ABO and RhD blood group distribution among pregnant women at a secondary level hospital in Nigeria. Methodology - This was a cross sectional study of healthy pregnant women attending Adeoyo Maternity Hospital, Ibadan, Nigeria. The record of every woman presenting for their first antenatal clinic visit over a 4-month period was reviewed. This included the results of haemoglobin electrophoresis and blood group. Results - Thirty four records were excluded because of incomplete data. The results for 2664 women are presented. The majority (70.1%) had normal haemoglobin (Mb AA), 29.5% were heterozygous for A (AS, AC) while 0.4% had abnormal Mb variants (SS, CC. SC). Rhesus D positive rate was 93.6%. Almost half (48.1%) were of blood group O, blood groups A and B were 23.5% vs. 24.9% respectively. The least blood group was AB. The ABO gene frequencies among these pregnant women were 0>B>A>AB. The phenotype frequencies with respect to ABO and Rhesus system were: O' > B > A > 0 > AB > A > B > AB Conclusion - The blood group distribution is such that availability of blood for transfusion will not be a challenge. Haemoglobin variants in this population are not uncommon. Genetic counselling for prospective couples, carrier screening and mutation identification arc important for reducing the sickling gene pool.