Objective: To compare perinatal results for multi-foetal pregnancies where the reduction was performed with pregnancies where the reduction was not performed. Setting: Sanatorium Pronatal, Na Dlouhé mezi 4/12, 147 00, Praha 4 - Hodkovičky. Methods: We have analyzed results of pregnancies, after delivery, for women with twin pregnancy which originated in our sanatorium, as a result of treatment with assisted reproducti on methods, in the period of time from January 1 st 1996 to December 31 st 1998. In the group being monitored there were 122 twin pregnancies originated as a result of reduction of triple and more-foetal pregnancies. We evaluated the percentage of miscarriages, length of pregnancies, weight of the newborns and the manner of termination of the delivery. These results were compared with our control group consisting of 180 cases of twin pregnancies which were not a result of reduction. Results: Analysis was performed for those mothers only where complete data were available. At a 5% level of statistical signifikance, it was not proved that both groups differed in average term of pregnancy or average weight of the twins. Average age of the mothers differed at 5% level of significance (average age values were 30.16 for the group with reduction and 31.73 for the group without reduction). Fisher test on 5 % significance level did not ascertain any signif icant differen- ce in the probability of miscarriage between the group with reduction (5.26 %) and the group without reduction (12.84 %). At 5% level of statistical significance, no significant difference in probability of perinatal death of the foetus or delivery of a stillborn foetus was ascertained. However, it is necessary to point out a low frequency of these phenomena in our group. The percentage of cesarean sections did not differ significantly in both groups (86.24 % in the group monitored vs 87.24 % in the group of twins without reduction).Conclusion: The analysis of both groups proves that reduction of multi-foetal pregnancies does not worsen perinatal results in comparison to pregnancies where reduction was not performed.

        Key words: reduction of multi-foetal pregnancies, miscarriages, lenght of pregnancies, weight of