Radiological aspects of fetal intrauterine transfusion.

Abstract

WITHIN THE past few years, considerable progress has been made in the management of erythroblastosis fetalis. Although introduction of high-titer anti-D gamma globulin (RhrrGam)2 will inevitably decrease the potential population who might require intrauterine transfusion (IUT), the already highly sensitized mother cannot be treated with RhoGam and must still be controlled by IUT. Therefore, further development and refinement of procedures must be continued. Intrauterine transfusion is dependent upon several roentgenographic technics— radioisotopic localization of the placenta, grid localization of the fetus, localization of the fetal abdominal structures by injection of radiopaque medium, and fluoro-scopic placement of the transfusion needle. Ease of performance and low morbidity (to both mother and fetus) of the aforementioned procedures are just as important as the quality and quantity of information that can be obtained. Since intrauterine transfusion is still in the adjustment phase and newer approaches must be devised to overcome problems of the current technic, the authors will present the roentgenographic methods employed at the Yale-New Haven Medical Center. Results and complications related to these radiographic procedures will be discussed. Materials and Methods All patients who exhibited Rh sensitization (positive maternal blood Coombs titer of 1:8 or greater) in the current pregnancy or in a previous one were considered candidates for further evaluation by amnio-centesis and spectrophotometric analysis of the amniotic fluid. The initial step for each patient was localization of the placenta by radioisotopic scanning. The patient was given Lugol's solution followed by an injection of 10 µCi of albumin-tagged 131I. After fifteen minutes a scintillation scan of the abdomen was obtained. The area of the placenta was revealed by elevated counts. Whenever possible, amniocentesis was initially undertaken at twenty weeks gestation and at appropriate intervals thereafter. If spectrophotometric analysis revealed an optical density difference in the upper quarter of Zone II or in Zone III in a pregnancy of less than thirty-two weeks gestation, the patient was considered a candidate for repeat amniocentesis and possible intrauterine transfusion. Once the clinical and laboratory findings indicated the necessity for intrauterine fetal transfusion, the next step was the determination of the lie of the fetus and the location of the fetal abdomen. A wire grid was placed over the maternal abdomen (Fig. 1, A), and an anteroposterior radiograph was taken (Fig. 1, B). The fetal skeletal structures could thus be related to the grid markings. If the fetus was in a direct anteroposterior lie, a lateral film was obtained to determine whether the spine was anterior or posterior (Fig. 1, C).