LAUSR

BACKGROUND Fetomaternal hemorrhage (FMH) can lead to severe, life-threatening fetal anemia depending on the amount of blood loss. FMH may be underdiagnosed as it is not routinely tested. In our report, we present a rare case of obvious mixed-field agglutination of maternal ABO forward typing caused by massive fetomaternal hemorrhage. METHODS We retrospectively evaluated the clinical information of a 42-year-old pregnant woman who was admitted to our hospital at gestational week (GW) 36_5/7 due to fetal distress. She later delivered a male infant with severe anemia by cesarean section. RESULTS This case had an unusual maternal hemoglobin elevation before delivery and the maternal blood type identification showed ABO discrepancy. After other causes were excluded, FMH was suspected. The Kleihauer-Betke (K-B) test was done on the mother's blood, indicating a massive FMH. CONCLUSIONS Massive FMH may be a cause of ABO discrepancy of pregnant woman. FMH should be considered when we get a result of a mixed-field agglutination of pregnant woman with other possible causes excluded.