Section 1—Factors in Pregnancy Affecting the Child

Résumé. Ľobservation ci‐dessus concerne une enfant soumise àľaction du radium au troisième mois de la vie intra‐utérine. II existait chez elle, une microcéphalic, uue arriération psycho‐motrice, un uanisme, un syndrôme ?insuffisance rénale avec raehitisme. Le radium a agi, semble‐t‐il, sur le développement du système nerveux central, mais aussi sur celui des reins. Summary1)  I. n. is duo to isoaggluthiation (and isohaemolysis). As to its clinical course it may be an icterns neonatorum lexis or gravis. As to the antigens and antibodies leading to isoagglutination the icterus is either an ABO‐icterus or an Rh‐icterus. 2)  As a rule, the levis form is an ABO‐icterus. the gravis form is an Rh‐icterus, there being, however, exceptions. 3)  The ABO‐agglutinogens are soluble in water, the Rh‐agglutinogens are not. Thus the former are present in the body‐fluids (at least in secretors), the latter are not (or only in vestiges). The ABO‐agglutinins of the mother react on the corresponding agglutinogens contained in the blood stream and on the body fluids of the fetus yet nothing prevents the anti‐Rh agglutinins from gaining access to the erythrocytes and the parenchymatous organs. It is for this reason that Rh‐icterus takes a more serious course and has an unfavorable prognosis. 4)  The constellation promoting Rh‐icterus (Rh‐agglutinophilia) is considerably more frequent than icterus neonatorum gravis. ABO‐auglutinophilia favoring ABO‐iclerus is. on the other hand. considerably less frequent than the actually observed cases of icterus neonatorum levis. The not yet satisfactorily explained difference amounts to 10% of all pregnancies in both eases, and is, no doubt, due to the fact that Rh‐icterus often takes the clinical form of icterus neonatorum levis and is recorded with the levis cases, thus ostensibly increasing the number of the latter. The gap existing between the number of cases of ABO‐agglutinophilia and of actually observed cases of icterus neonatorum levis is thereby filled. 5)  In the rare cases in which an Rh‐positive mother's child is suffering from icterus gravis (or other forms of morbus haemolyticus neonatorum), the role of as yet undiscovered agglutinogens and agglutinins has to be assumed. It is, however, probable that in the majority of instances they are nothing but extremely grave cases of ABO‐ieterus.