Analysis of laboratory tests and prevention strategies for hemolytic disease of the fetus and newborn caused by anti-M

Abstract

Objective To analyze the application of serological test results in the diagnosis and treatment of anti-M-induced hemolytic disease of the fetus and newborn(HDFN), and to explore HDFN prevention strategies. Methods The serological test results of 12 cases of HDFN caused by anti-M diagnosed in our laboratory from January 2017 to December 2023 were retrospectively analyzed, including blood group identification of mothers and children, serum total bilirubin/hemoglobin/antibody titer test, and three hemolysis tests in newborns. Clinical data of the children and mothers were collected, including pregnancy history, blood transfusion history, prenatal antibody testing, history of intrauterine blood transfusion and gestational week of delivery, and the prognosis of the children was followed up. Results All 12 cases of fetal neonatal hemolytic disease due to anti-M were RhD+ MN phenotype newborn born to RhD+ NN mother, with maternal- fetal incompatiblility in MN blood groups. In the ABO blood group system, ABO incompatibility between mother and child accounted for 41.7%(5/12).None of the mothers had a history of blood transfusion, and the median titer of the test at 4℃ was 32, and the median titer at 37℃ was 4. The mothers of 3 cases had a history of multiple intrauterine blood transfusions, with an incidence of 25%(3/12). One case had an abnormal first pregnancy, with an incidence of 8.3%(1/12), and seven cases had an abnormal pregnancy with a miscarriage, with an incidence of abnormal pregnancy and birth history of 58.3%(7/12). There were 6 cases of premature labor, with an incidence of 50%(6/12). The mothers in three cases underwent regular obstetric examination and the specificity of the antibodies was determined, accounting for 25%(3/12). Twelve children had free antibodies with a median titer of 6 at 4℃ and 2 at 37℃. Two children had anti-M antibodies that were not reactive at 37℃, with a negative rate of 16.7%(2/12). The positive rate of DAT and elution test was respectively 8.3%(1/12) and 16.7%(2/12) in the children. The median minimum hemoglobin value was 75 g/L, and all 12 children received blood transfusions. The median peak total bilirubin value was 157.5 μmol/L, and none of them reached the threshold for blood exchange. The rate of delayed anemia was 16.7%(2/12), the postnatal mortality rate was 8.3%(1/12), and 11 children was free of growth and neurodevelopmental delay in prognosis. Conclusion Anti-M can cause severe HDFN, which can also occur in primigravida. The intensity of antibody titer does not correlate with the severity of the disease, and it is prone to cause delayed anemia, which should be monitored regularly according to the serological characteristics of anti-M and clinical symptoms, and should be treated timely.

Keywords

• anti-m
• hemolytic disease of the fetus and newborn(hdfn)
• prevention strategy