The probability of ABO incompatibility
The blood group phenotypes were used to calculate ABO gene frequencies of 85 590 blood donors. The prevalence of blood group B (31.44%) was slightly higher than that of blood groups A (29.05%) and O (28.54%), and the distribution characteristics were B > A > O > AB in the Affiliated Hospital of Qingdao University in northern China (Fig. 1).
The probabilities of genes A, B, and O were 0.2253, 0.2409, and 0.5338, derived from the population frequencies of ABO blood group phenotypes in the recruited blood donors at the Affiliated Hospital of Qingdao University (the detailed calculation procedure is shown in Supplementary Information A).
The probability of a blood group O woman giving birth to an infant who was non-group-O was predicted to be 13.28% at the Affiliated Hospital of Qingdao University in northern China (the detailed calculation procedure shown in Supplementary Information B).