RESUMO
Background This study analyses the association between ABO blood group phenotypes in relation to placental malaria pathology. Methods A total of 198 mother/child pairs delivering in Banjul and the Kombo-St Mary District (The Gambia) were analysed. ABO blood group was measured by agglutination. Placental malaria parasites were enumerated and the presence of malaria pigment noted. Birth anthropometry was recorded and placental weight. Maternal and infant haemoglobin was measured. Results 89 (45) subjects were primiparae and 110 (55) multiparae. The ABO phenotype distribution was 38(A); 52(B); 6(AB) and 102(O). Placental histo-pathology showed active placental malaria in 74 (37); past infection in 42 (21) and no infection in 82 cases (41). In primiparae; blood group O was associated with a higher risk of active infection (OR= 2.99; 95CI= 1.24-7.25); and a lower risk of past infection (OR = 0.31; 0.10-1.01; p0.05). In multiparae; the O phenotype was associated with reduced prevalence of active or past placental infection (OR