[In utero treatment of fetal anemia]

Fetal anemia may be central or peripheral and results in fetal hyperflow that progresses to hydrops, a state of generalized edema (a therapeutic emergency because it carries a high risk of fetal death). Diagnostic suspicion is based on ultrasound measurement of peak systolic velocity in the middle cerebral artery, which is then increased. The primary cause is anti-D alloimmunization, followed by parvovirus B19 and then anti-Kell alloimmunization, both of which are associated with the risk of early anemia. Pregnancies at risk for fetal anemia should be monitored by a fetal medicine center. In utero transfusion is performed under aseptic surgical conditions and ultrasound guidance. It must be performed only in expert centers. In general, anemia can be cured without any consequences for the fetus, although there is a risk of complications and in case of hydrops, there is a risk of cerebral lesions and delayed neurodevelopment.