Relationship Between IgG Antibody Titer and ABO Hemolytic Disease of Newborn

[Objective] To study the relationship between IgG antibody titer and ABO hemolytic disease of newborn. [Methods] A total of 785 gestational women with O blood group whose husbands were the other blood group except O and 794 newborn were chosen. Serum IgG antibody against A and B of red blood cells of pregnancy women was examined. The efficiency≥1∶64 were positive, and reexamination was done in time during pregnancy. Red blood cells were taken from umbilical vein to do the following four examinations when delivery:①blood type; ②coomb's test; ③free antibody detection; ④liberation test. The newborns diagnosed as ABO haemolytic disease were examined for their red blood cells, Hb, net blood cell, total bilirubin and type. [Results] The positive rate of AbA and AbB of the gestational women with more than one time pregnancy was higher than that with only one pregnancy. The difference was significant (P0.05). The positive rate of the elder women was higher than that of the younger women, but the difference wasn't significant (P0.05). Comparing between the newborns with O blood group and others with A or B blood group, IgG antibody titers of their mothers were supplied differently, but the difference wasn't significant (P0.05). The incidence of haemolytic disease of newborn increased when IgG antibody titer against A and B increased. The correlation coefficient was 0.756 (P0.05), but the incidence rate of haemolytic disease of the newborn did not increase when the antibody titer increased (P0.05). [Conclusion]The pregnant women who have many times of pregnancy, and are elder or have history of abnormal pregnancy should be examined for the titer of IgG antibody against A and B in the early period of pregnancy. Dynamic observation should be taken during pregnancy. Serum IgG antibody titer in maternal serum should not be the only evidence for diagnosing fetal haemolytic disease and its prognosis. Therefore it is necessary to measure amniotic fluid or umbilical blood and the level of bilirubin, and to examine the blood type and to do the diagnostic test for the conditioned person.