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 pregnancies.

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 ultrasonographic signs of hydrops at the start of treatment; 42 of these were classified as mildly hydropic and 38 were classified as severely hydropic. Reversal 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 mild hydrops and 39% in fetuses classified as severely hydropic. After reversal of hydrops, almost all of the fetuses survived (98%), whereas in cases of persistent hydrops outcome was unfavorable, with a survival rate of 39% for all fetuses and 26% for fetuses classified as severely hydropic.

CONCLUSION

In contrast with severe hydrops, there is a high rate of reversal of mild hydrops after adequate treatment. In our study 98% of fetuses survived 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 intrauterine treatment when hydrops is absent or still mild.