Ultrasound contributions to the management of the severely isoimmunized fetus

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Abstract
Twenty-four out of 81 fetuses affected by anti-D isoimmunization underwent ultrasonic guided intrauterine transfusions (2.8 I.U.T.s per fetus). The absolute value and trend of .DELTA.OD 450 micron value was correlated with the severity of fetal condition as evaluated by ultrasonography following simple semiquantitative grading of ascites (mild, moderate, severe) and diagnosis of hydrops. The evaluation of disease was monitored in this way during transfusion therapy. Transfusion procedures have been ultrasonically guided. When ascites was present a few mililiters of isolytic solution allowed the bubbling effect to be observed. In the case of no ascites we confirmed the needle positioning by a cineradiographic sequence lasting a few seconds. Fetal transfusions were repeated every 10 to 15 days and the amount of packed red cells to be injected was determined according to the week of gestation. Post-transfusion monitoring included ultrasonic reevaluation of fetal parameters and non-stress testing. All fetuses were delivered via cesarean section before the 35th week of gestation. In no case was treatment started after the 31st week. Seventeen fetuses were transfused before the 26th week (71%). In 13 fetuses transfusions were started before ascites had appeared. Only 5 fetuses worsened and the 3 which became hydropic eventually died. The .DELTA.OD-450 value of these 5 cases before therapy had already indicated that they were more severely affected. Survival rate in this group was 69%. Eleven fetuses showed different degrees of ascites or hydrops at the time of the first transfusion. A marked improvement was observed only in the 3 cases in which treatment was started early and/or with only a mild to moderate ascites. Survival rate in this group was 36%. No fetal loss occurred after 29 weeks. Three fetal deaths occurred within 24 hours after I.U.T. Three neonatal deaths occurred at 29 (marked cardiomegaly), 32 (severe hydrops) and 31 weeks (severe hydrops). The transformation of intrauterine fetal transfusion into a relatively simple procedure is the most evident contribution provided by ultrasound to the management of anti-D immunized pregnancies. In the present series we observed only 2 (3%) failed attempts, 1 (1.5%) subcutaneous traumatic lesion and 3 (3.3% fetal losses per I.U.T.). Between 1974 and 1978 in our Centre 5.5% of fetal traumatic losses attributable to the transfusion procedure occurred in 85 patients transfused in utero under X-ray control. These results are in fact similar to those reported by different centres. Moreover the proportion of survivors rose in the two series from 13% to 36% in hydropic fetuses and from 51% to 69% in non-hydropic fetuses. In recent papers, as well as in our own experience, ultrasound has played an important role in monitoring fetal conditions. This allows the physician to perform scheduled amniocentesis and I.U.T.s earlier in worsening cases. We chose to express the evaluation of the fetal condition as judged by sonography, of ascites developing into hydrops. These gross sonographic parameters we adopted matched the .DELTA.OD values well. The absolute value and trend of .DELTA.OD-450 before I.U.T. in the cases which developed ascites after the first I.U.T. are much more similar (p = n.s.) to those already in this state at the time of first transfusion than to persistently non-asitic fetuses (u < 0.05), similarly in the ascitic fetuses in the three fetuses in which an improvement was oserved after the transfusions, the .DELTA.OD-450 was lower than in the other fetuses in their group.

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