Abstract: Objective To study the incidence of ABO hemolytic disease of newborn and analyze the relationship between ABO hemolytic disease of newborn and prenatal antibody titer of maternal. Methods From January 2021 to December 2022, women with O blood group who were incompatible with their husband and gave birth in Haikou Maternal and Child Health Hospital and Danzhou Maternal and Child Health Hospital were selected for this study. The antibody titer was determined by anti-human globulin microcolumn gel method. ?After delivery, ABO hemolytic disease of newborn was detected and analyzed, and the relationship between ABO hemolytic disease of newborn and prenatal antibody titer of O blood maternal was analyzed. Results A total of 1 006 effective subjects were obtained, with an effective rate of 91.70%. There were 398 cases of O-A type, 371 cases of O-B type, and 237 cases of O-AB type in couples, accounting for 39.56%, 36.88%, and 23.56%, respectively. The distribution of IgG antibody titer in serum of pregnant women ≤1∶32, 1∶64, 1∶128, 1∶256, 1∶512, and>1∶512 accounted for 17.20%, 22.56%, 20.38%, 22.37%, 10.04%, and 7.46%, respectively. There were 251 cases of ABO hemolytic disease of newborn were detected, with a positive rate of 24.95%. The positive rates of ABO hemolytic disease of newborn of couple blood type O-A, O-B, and O-AB were 22.36%, 24.26% and 30.38%, respectively, and there was no significant difference between groups （P>0.05）. The detection rate of ABO hemolytic disease of newborn with IgG antibody titer distribution ≤1∶32, 1∶64, 1∶128, 1∶256, 1∶512, and >1∶512 in maternal serum were 0.00%, 11.45%, 32.68%, 38.67%, 39.60% and 41.33%, respectively, and the difference between the groups was statistically significant （P<0.05）. Multivariate Logistic regression analysis showed that IgG antibody titer （OR=2.415, 95% CI：1.329-5.974） of pregnant women was a related factor of ABO hemolytic disease of newborn. Conclusions ABO hemolytic disease of newborn is closely related to the prenatal antibody titer of O blood maternal. With the increase of antibody titer, the prevalence of ABO hemolytic disease of newborn increases. The blood type IgG antibody titer of pregnant women suggested to detect before delivery, which is of great significance for the prevention and control of ABO hemolytic disease of newborn.

Key words: ABO hemolytic disease of newborn, Type O blood, Maternity, Prenatal, Antibody titer