Conventional management of maternal red cell alloimmunization compared with management by Doppler assessment of middle cerebral artery peak systolic velocity

Objective This study was undertaken to compare management of red blood cell alloimmunization by Doppler measurement of middle cerebral artery peak systolic velocity (MCA-PSV) to conventional management with amniocentesis. Study design A historical cohort of 28 fetuses at risk for anemia caused by red blood cell alloimmunization was followed between 1999 and 2002 at a single institution. The decision to perform percutaneous umbilical cord blood sampling (PUBS) was based on conventional management. MCA-PSV Doppler was measured before amniocentesis or PUBS but not used clinically. Results Twenty-eight fetuses were followed up: 4 had severe anemia, 1 had moderate anemia, 3 had mild anemia, and 20 were nonanemic. Conventional management had a sensitivity and positive predictive value for moderate-to-severe anemia of 80% and 44%, with a false-positive rate of 56%. In the same patients, MCA-PSV Doppler had a sensitivity and positive predictive value for moderate-to-severe anemia of 100% and 71%, with a false-positive rate of 28%. Conclusion Compared with conventional management, MCA-PSV Doppler may have a better predictive accuracy for moderate-to-severe fetal anemia in red blood cell alloimmunization. Management by MCA-PSV Doppler may eliminate the need for amniocentesis and reduce the number of PUBS performed in red blood cell–alloimmunized pregnancies.