American Journal of Perinatology Reports

Anti-M red blood cell (RBC) alloantibodies are observed in 0.3% of pregnant women, 1 in which it causes hemolytic disease of the fetus/newborn; currently, no standard treatment method has been established.It is managed by plasmapheresis and high-dose intravenous immunoglobulin (IVIG) therapy that are conventionally used for treating Rh blood-type alloimmunization during pregnancy.We report a unique case of a pregnant woman who had intrauterine fetal death (IUFD) in two previous pregnancies; the detected titers of anti-M antibodies were very low.Informed consent was obtained from the mother for publication of this case report. Case ReportA 25-year-old woman presented to us at 8 weeks of pregnancy with a history of IUFD in two previous pregnancies.Following blood testing, a 16-fold increase in immunoglobulin (Ig)G-type anti-M antibody titer was observed during her first pregnancy (age, 21 years), which ended in IUFD at 36 weeks.In her second pregnancy (age, 23 years), anti-M antibodies were detected at 12 weeks, which increased 64-fold at 15 weeks, and resulted in hydrops fetalis and IUFD at 19 weeks.Blood type analysis revealed type O ccDEE