[Clinical comparison of four types of IUDs made in China].

In order to compare the clinical efficacy of 4 types China made IUDs, this paper reported the study of a total of 1227 cases who, from January 1973 to June 1975, had used 1 of the 4 types of IUDs -- the stainless steel ring, metallic plastic mixed ring, metallic and silastic copper-shaped devices. The study was not a random allocation but was done, 1 type by 1, during the period. Life table method and logrank test were used to calculate and analyze the different events among these 4 types. 1147 cases were followed up for more than 5 years. The 5-year followup rate was 93.48%. Patients using these 4 types were comparable among themselves since the distribution of their age, gravida, para, and time of insertion were the same or quite similar. Study results were as follows: the cumulative pregnancy rates of the 2 copper V-shaped IUDs were significantly lower than that of the steel and mixed ring (p0.01); the cumulative expulsion rate of the steel ring was comparatively high, but there was no statistical difference compared with the others; bleeding was the main cause of medical removals; there was a higher cumulative medical removal rate of the V-shaped than that of the ring-shaped and also a significant difference between them (p0.01). However, at every year, the year-cumulative continuation rates were similar despite the difference of the events of discontinuation rates. The fact that 51.72-62.29% of the subjects continued to wear these IUDs indicated that the efficacy of the 4 types of IUDs was satisfactory even after a 5-year course.