Blood in amniotic fluid following intrauterine transfusion and its effect on premature onset of labor.

The most frequent cause of perinatal death following intrauterine transfusion in cases of severe rhesus hemolytic disease remains premature onset of labor and the resulting newborn so delivered. In the present study, 70% of all perinatal deaths were directly related to immaturity. A factor of decisive importance as an initiator of labor before the intended time is the leakage of blood into the amniotic fluid at the time of the procedure. (Mostly, this blood seems to originate from the fetal abdomen into which it was injected for therapeutic reasons.) The effect of blood-contaminated amniotic fluid on uterine activity is demonstrated on the material from Lewisham Hospital of London, where between 1 and 5 intrauterine transfusions were performed on 517 patients during a period between November 1963 and the end of March 1973. The presence of blood in the amniotic fluid was proved either by means of amniocentesis performed 2 days after intrauterine transfusion, or at the time of membrane rupture in labor. Patients who received a self-retaining catheter for any length of time were excluded from the material since the additive influence of the catheter on labor could not be assessed. Out of a total of 452 cases receiving single-use catheters, there were 208 cases (46%) with premature onset of labor. In 2-thirds of the cases this happened within the first week after the last intrauterinetransfusion. Further investigation of 332 case-histories with complete records was carried out. In 61.6% of the patients with labor before the intended time within 21 days after the last intrauterine transfusion, blood contaminated amniotic fluid was found, whereas this occurred in only 34.8% of the cases without premature onset of labor (p less than 0.001). From the same material, corresponding percentages for livebirths and stillbirths were calculated. As a consequence of these results, it is recommended that patients be kept under intensive hospital care following intrauterine transfusion whenever blood can be proved to be present in the amniotic fluid. Prophylactic measures to prevent premature onset of labor should also be considered.