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.