142 cases of erythrocyturia in the prepartal period were reexamined 3 months post partum. 15.5% of those examined already showed pyelonephritic changes in the uriograph and 57.6% had a corresponding anamnesis. Erythrocyturia was present in only 24.6% of cases 3 months post partum and in 12.5% of cases after 3 years. After 3 years there were no pathological urine findings in 70.8%. Because kidney punction gives rise to histological changes which are hard to detect and present an unacceptable risk, it is only indicated if the condition is observed over a long period--at least 2 years--and other procedures of nephrological examination have been exhausted. In a few cases it will already be necessary within the first year, with due attention given to therapeutic consequences. Equivalents of infection of the urinary passage and glomerular lesions should be treated and observed at a special kidney clinic over a period of years.