Long-term follow-up after quinacrine sterilization in Vietnam. Part II: interim safety analysis.

OBJECTIVE To determine the long-term safety of nonsurgical sterilization with quinacrine. DESIGN Observational cohort study. SETTING Rural provinces in northern Vietnam. PATIENT(S) Two thousand eight hundred forty women who had had quinacrine insertions and an age-matched comparison group of 1,658 women who had an intrauterine device (IUD) insertion between 1989 and 1993. METHOD(S) Interviews in 1994, 1995, and 1996 and review of available medical records. This is a planned interim analysis. MAIN OUTCOME MEASURE(S) Ectopic pregnancies and the occurrence of other adverse health events. RESULT(S) Over 90% of women were interviewed at least once. Despite matching on age, the groups differed on baseline parity. The ectopic pregnancy rates were similar after either one or two insertions and were similar to the rate of ectopic pregnancies after surgical sterilization in the United States. The quinacrine group reported more gynecologic health problems than the IUD group. However, after correcting for information bias, there was no dose-response effect between the one- and two-insertion quinacrine groups, suggesting the possibility of recall bias or differing baseline health status. CONCLUSION(S) Ectopic pregnancies do not appear to be increased compared with U.S. surgical sterilization rates. The data on other adverse events are more difficult to interpret.