摘要：The effectiveness of contraceptive methods, such as I.U.D. can be considered with different points of view, such as: The period of protection from pregnancy for such married couple. The demographic effect of the program, on the basis of the number of births, averted in a given population. The objective of the, present study was to calculate the probability of pregnancy, expulsion, removal and the continuation rate in use of I.U.D.The present study which started on the first month of 1973 and ended in July 1975 (28 month) covered 11120 women, who referred to the Farmanfarmaian clinic in Tehran for insertion of I.U.D. The data were analyzed using the life table method. The results of the study was as follows: Probability of pregnancy after one year 7.6 per thousend, this figure is 3-6 times less than rates reported elsewhere and cannot be considered to be reliable, because the sample size was not adequate, also due to the lack of a proper follow up program, it is possible that the pregnancies are under reported. Expulsion rate, after the year was 8.12%, which is in accord with the studies and the removal rate was 12.81 %. It is interesting to note that from the 5th month onward the probability to removal of I.U.D. is more than that of expulsion. This may be either due to the severity of complications in the later months of use or referrals for removal as time proceeds. The continuation rate after six months was 8.46% and after one year 7.83%.
