Management of pregnancies complicated by anti-Fya alloimmunization

BACKGROUND: The objective was to evaluate the management and outcome of patients with anti-Fy(a) at the Ohio State University. STUDY DESIGN AND METHODS: A database search for patients with pregnancies complicated only by anti-Fy(a) from 1959 to 2004. Collected information included maternal testing, fetal therapy, and neonatal outcomes. RESULTS: The final data set included 18 pregnancies in 15 women where anti-Fy(a) was the only maternal alloantibody present and the fetus was Fy(a) antigen-positive. Maternal antibody titers of at least 32 and optical density at 450 nm values in modified Liley Zone IIB or III identified all fetuses or neonates with significant hemolytic disease (2/18, 11%). No fetuses had hydrops, and there were no deaths attributed to hemolytic disease of the fetus and newborn. CONCLUSION: Anti-Fy(a) has the potential to lead to significant fetal hemolysis. Management guidelines developed for D sensitization are appropriate for pregnancies complicated by anti-Fy(a) alloimmunization.