If risk of the one-time mechanical dilatation will be too high (with young first gravidae and progressed pregnancy) the methods of the two-time interruptio should be applied. As long as there will not be available sufficient quantities of Prostaglandin-analoga the present method of choice is the abort-induction by means of the extra-amnial application of Prostaglandin F2alpha. In 101 cases when extra-amnial Pg F2alpha with an average induction time of four hours, the contamination rate was checked and no danger of ascension appeared. If prostaglandines will not be available, metranoicter or laminarias should be applied in the first trimenon when there is a high risk of dilatation, in the second trimenon extra-amnial instillation methods should be used. In both the cases only can be spoken of interruptios low if risks of they are made up under guard of broad spectrum antibiotics--after negative proof of blastomyces (buddings). This recommendation results from microbiological researches made up with 423 patients under the aspect of possible hospital infections. With induction times longer than 18 hours, the cavum uteri proved accelerating contaminated microbially. There were found microbes in the cavum uteri respectively at laminarias and metranoicters of, enterobacteria (45,7%), staphylococci (24,7%), hemolyzing and anhemolytic streptococci (17,6%), enterococci (8,0%), Corynebacteria (3,0%) and blastomyces (buddings) (1,0%).