Fetomaternal hemorrhage is known to have a wide spectrum of clinical presentations. This large variability probably explains why there are still neither consensual classification nor management recommendations. Nevertheless, fetomaternal hemorrhage is a serious condition, which may cause life-threatening fetal anemia. Fetal tolerance mainly depends on the quantity of fetal blood loss as well as the rate at which it occurs. Decrease in perceived fetal movements represents the main clinical sign of fetomaternal hemorrhage and justify use of diagnostic tests such as the Kleihauer-Betke test. Large fetomaternal hemorrhages can also induce fetal hydrops and stillbirth. In this review, we emphasize the clinical and biological features of fetomaternal hemorrhages and we highlight the circumstances associated with false-negative and false-positive results of the Kleihauer-Betke test. We also propose an original algorithm for the management of fetomaternal hemorrhages.