SummaryIn this paper the following problems are discussed :1. The influence of a pregnancy of the morphology and function of the kidney.2. Some aspects of the water and salt metabolism during pregnancy.3. The role of some renal factors in the pathogenesis of the syndrome of prae-eclampsia. Some controversies about the prophylactic use of salt restriction and diuretics are discussed.4. The occurence and significance of hypertension during pregnancy.5. The problem of the asymptomatic bacteriuria of pregnancy.6. Some aspects of the influence of pregnancy on a preexistant kidney disease.