In the period from October 1984 to December 1993, 1657 cases of Norplant implantswere observed, and menstrual records of the first 548 subjects were returned and analyzedfor vaginal bleeding patterns in users of the Norplant implants. Results showed: The average total number Of vaginal bleeding days and the number of spotting days in the firstreference period of 90 days was 33. 0 days and 21. 5 days, respectively; in the 4th reference period (at one year) it was 26. 7 days and 13. 8 days, respectively. The number wasdecreased further in the 20th reference period to 20. 2 days and 9. 5 days. Amenorrhea accounted for 0. 5~ 5. 4% women in different reference periods. Conclusions: Use of theNorplant implants showed the gradual decrease of the average total number of vaginalbleeding days with the passage of time, mainly, the decrease in spotting days. The occur-rence of bleeding days and profuse bleeding days did not show any great change. In the period from October 1984 to December 1993, 1657 cases of Norplant implantswere observed, and menstrual records of the first 548 subjects were returned and analyzed for vaginal bleeding patterns in users of the Norplant implants. Results showed: The average total number Of vaginal bleeding days and the number of spotting days in the first reference period of 90 days was 33. 0 days and 21. 5 days, respectively; in the 4th reference period (at one year) it was 26. 7 days and 13. 8 days, respectively. The number wasdecreased further in the 20th reference period to 20. 2 days and 9. 5 days. Amenorrhea accounted for 0.5 to 5.4% women in different reference periods. Conclusions: Use of the Plant implants showed the gradual decrease of the average total number of vaginalbleeding days with the passage of time, mainly, the decrease in spotting days. The occur-rence of bleeding days and profuse bleeding days did not show any great change.