[Duration of use for stainless steel ring--15 years of follow-up for 6250 cases].

This study was to observe the longterm safety in using stainless steel ring (metal ring). 6250 cases have been followed up for 15 years. The net cumulative pregnancy rate was 5.51, expulsion rate 17.74, rate of removal due to medical reasons 21.74, continuation rate 6.48/women (life table) after 15 years of insertion. Events took place more frequently in the 1st year of insertion, gradually decreased in the second, and tended to be stabilized to a low level thereafter. The removal rate for nonmedical reasons had been increasing with the increase in the period of insertion. 5 cases of cervical cancer and 2 of endometrial carcinoma occurred within the 15 years of observation. The incidence was not higher than that in the 1971-72 general survey at Shanghai. Among the 6250 cases, there were 43 cases (0.85%) of removal due to infection, and 9 cases of ectopic pregnancy, of which 6 cases occurred within the first 2 years of insertion, and 2 cases of intraperitoneal metal ring were found but with no severe complications. The duration of using the metal ring was also discussed. According to clinical and pathological observations, the metal ring did not increase the risk of uterine cancer and caused only a few mild complications. Therefore, it can be used for 15-20 years, provided there are no clinical symptoms. The relationship between the IUD and ectopic or PID remains to be further explored.