A study evaluated the use of Doppler ultrasonography to noninvasively diagnose fetal anemia caused by maternal red-cell alloimmunization. Invasive methods like amniocentesis and cordocentesis are currently used for diagnosis and treatment. The study measured the peak systolic velocity of blood flow in the middle cerebral artery (MCA) in 111 fetuses at risk for anemia. The results showed that an increased MCA peak systolic velocity was 100% sensitive for detecting moderate or severe anemia, with a 12% false positive rate. This method was effective regardless of the presence of hydrops. The study concluded that Doppler ultrasonography can noninvasively detect moderate and severe anemia in fetuses at risk due to maternal red-cell alloimmunization. The study also found that the MCA peak systolic velocity is a strong predictor of anemia, even in cases of Kell sensitization. The results suggest that this method is accurate and noninvasive, reducing the need for invasive procedures like cordocentesis. The study highlights the potential of Doppler ultrasonography as a reliable tool for diagnosing fetal anemia without the risks associated with invasive methods. The findings support the use of Doppler ultrasonography for noninvasive diagnosis of fetal anemia due to maternal red-cell alloimmunization.A study evaluated the use of Doppler ultrasonography to noninvasively diagnose fetal anemia caused by maternal red-cell alloimmunization. Invasive methods like amniocentesis and cordocentesis are currently used for diagnosis and treatment. The study measured the peak systolic velocity of blood flow in the middle cerebral artery (MCA) in 111 fetuses at risk for anemia. The results showed that an increased MCA peak systolic velocity was 100% sensitive for detecting moderate or severe anemia, with a 12% false positive rate. This method was effective regardless of the presence of hydrops. The study concluded that Doppler ultrasonography can noninvasively detect moderate and severe anemia in fetuses at risk due to maternal red-cell alloimmunization. The study also found that the MCA peak systolic velocity is a strong predictor of anemia, even in cases of Kell sensitization. The results suggest that this method is accurate and noninvasive, reducing the need for invasive procedures like cordocentesis. The study highlights the potential of Doppler ultrasonography as a reliable tool for diagnosing fetal anemia without the risks associated with invasive methods. The findings support the use of Doppler ultrasonography for noninvasive diagnosis of fetal anemia due to maternal red-cell alloimmunization.