Clinical Characteristics Associated with Fetomaternal Hemorrhage: A Retrospective Multicenter Descriptive Study...

Fetomaternal hemorrhage refers to the transfer of fetal erythrocytes into the maternal circulation. Although clinically significant fetomaternal hemorrhage is rare, it can result in severe fetal anemia with substantial morbidity and mortality. Early recognition remains challenging due to a nonspecific clinical presentation. This study aimed to identify maternal and obstetric characteristics associated with fetomaternal hemorrhage that may serve as early clinical warning signs. In this retrospective multicenter descriptive study, singleton pregnancies with a positive Kleihauer-Betke test from five obstetric care centers in Berlin (2009-2026) were analyzed. Clinical and demographic data were evaluated descriptively. A total of 39 cases were included. The mean maternal age was 31.9 years and the mean gestational age at delivery was 37.3 weeks. Pathological cardiotocography was observed in 79% of cases, including 42% with a sinusoidal pattern. Reduced fetal movements were reported in 51% of cases. Elevated middle cerebral artery peak systolic velocity, suggestive of fetal anemia, was documented in 50% of cases with an overall documentation rate of 31%; abdominal trauma was present in 15% of cases. Caesarean section was performed in 82% of cases, including 31% emergency procedures. Intrauterine fetal death occurred in 5% of cases. Reduced fetal movements and abnormal cardiotocography patterns, particularly sinusoidal tracings, represent key clinical warning signs of fetomaternal hemorrhage and should prompt immediate diagnostic evaluation. Given the small sample size, findings are exploratory. Prospective studies are needed to establish validated risk profiles and diagnostic pathways.