The severity of immune fetal hydrops is predictive of fetal outcome after intrauterine treatment

OBJECTIVE: This study was undertaken to test the hypothesis that the degree of immune fetal hydrops predicts outcome in red blood cell-alloimmunized p regnancies. STUDY DESIGN: In an 11 -year period, 213 fetuses received 599 intrauterine transfusions. The outcome of 208 pregnancies, including two pairs of twins, was analyzed in a retrospective study. Eighty fetuses demonstrated ultraso nographic signs of hydrops at the start of treatment; 42 of these were clas sified as mildly hydropic and 38 were classified as severely hydropic. Reve rsal of hydrops as a result of treatment, survival, and neonatal morbidity was studied. RESULTS: The overall survival rate of fetuses with hydrops was 78%. Of the fetuses with mild hydrops, 98% survived, whereas in cases of severe hydrops the survival rate was 55%, Intrauterine reversal of hydrops occurred in 65 % of the fetuses with hydrops. The reversal rate was 88% in fetuses with mi ld hydrops and 39% in fetuses classified as severely hydropic. After revers al of hydrops, almost all of the fetuses survived (98%), whereas in cases o f persistent hydrops outcome was unfavorable, with a survival rate of 39% f or all fetuses and 26% for fetuses classified as severely hydropic. CONCLUSION: In contrast with severe hydrops, there is a high rate of revers al of mild hydrops after adequate treatment. In our study 98% of fetuses su rvived after reversal of hydrops. To improve the outcome of red blood cell- alloimmunized pregnancies, early diagnosis of fetal anemia and referral to a specialized center are important; these steps enable the start of intraut erine treatment when hydrops is absent or still mild.