Fetomaternal hemorrhage refers to the entry of fetal blood into the maternal circulation before or during delivery. Antenatal fetomaternal hemorrhage is a pathological condition with a wide spectrum of clinical variation. Secondary to the resultant anemia, fetomaternal hemorrhage may have devastating consequences for the fetus such as neurologic injury, stillbirth, or neonatal death. Presentation is frequently without an evident precipitating factor. Recognition may become apparent only after injury has occurred, if at all. The most common antenatal presentation is decreased fetal activity and a heightened index of suspicion is warranted in cases of persistent maternal perception of decreased fetal movements. The diagnostic standard, the Kleihauer-Betke screen, has several limitations. Management remains challenging. When detected antenatally, cordocentesis with intrauterine transfusion may be attempted to correct the anemia; however, repeat intrauterine transfusion or delivery may be necessitated to correct ongoing bleeding. Although the occurrence of large antenatal fetomaternal hemorrhage is fortunately rare, this entity likely remains underreported and underrecognized. A national registry should be created to advance our learning across institutions by reviewing the clinical presentations of fetomaternal hemorrhage, the variety of fetal heart rate tracings observed, the management strategies undertaken, and the outcomes achieved.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, Massachusetts, USA. firstname.lastname@example.org