The isohemolytic reaction subsequent to the use of improperly matched blood in transfusions has the appearance of jaundice as one of its outstanding features. The reason for this complication probably lies in the sudden liberation of large amounts of hemoglobin. It has been suggested by Ottenberg1 that icterus neonatorum might be explained on a similar basis; namely, that it is due to the accidental transfusion of incompatible blood between mother and fetus through an opening in the placenta. My object in this paper is to present data bearing on the possibility of the blood group of mother and fetus being related to the development of icterus neonatorum.
Icterus neonatorum is generally regarded as the manifestation of a physiologic bilirubinemia which occurs most commonly from the second to the eleventh day of postembryonic life. The statistics of its frequency depend in large part on the observer's interpretation of jaundice. Von