PRENATAL TREATMENT OF ERYTHROBLASTOSIS FETALIS FOLLOWING HYSTEROTOMY

In recent years considerable progress has been made in diagnosis and treatment of the erythroblastotic fetus. Many aspects of the problem, however, remain to be solved. Perhaps the most urgent one is earlier diagnosis: delaying treatment until demise is imminent is unlikely to lead to optimal outcome. Interference in the transfer of bilirubin across the placenta is probably a late phenomenon, present only when placental perfusion is impaired and the diffusion distance is increased by stromal edema of villi. Hence, the currently accepted indications for operative intervention are present only when the fetus has been severely affected for some time. It is possible that changes in fetal heart rate, either spontaneous or in response to a given stimulus, might reveal an incipient anemia not yet reflected in the composition of amniotic fluid. Determination of the excretion pattern of chorionic gonadotropin might also be of value. Changes in the appearance of placental villi obtained by needle biopsy and examined by phase contrast microscopy have been helpful in diagnosing impending hydrops. The benefits of this procedure, however, must be weighed against the potential danger of increasing maternal sensitization. Optimal technique and timing for administration of red cells remain to be determined. Different approaches may be preferable at various gestational ages. Close to the time of extrauterine viability and in the absence of hydrops the method introduced by Liley may prove to be the most satisfactory. Earlier in gestation techniques which provide the fetus with an indwelling catheter, either intravascular or intraperitoneal, probably hold greater promise. Bone marrow as the site of infusion might offer advantages and should also be considered. Whether the insertion of a catheter is accomplished better during hysterotomy or by means of a transabdominal needle puncture with the aid of a fluoroscope or amnioscope, remains to be determined. For the hydropic fetus near term, exchange transfusion in utero might be lifesaving.