A randomized multicenter study comparing the efficacy and bleeding patternof a single-rod (Implanon (R)) and a six-capsule (Norplant (R)) hormonal contraceptive implant

To compare the contraceptive efficacy, tolerability, and bleeding patterns, 200 healthy female volunteers received, in an open, comparative, randomize d, multicenter study in China, either a single-rod (Implanon(R)) or a six-c apsule (Norplant(R)) contraceptive implant for 2 years with an optional ext ension of up to 4 years. Women were exposed to Implanon for 341.6 woman-yea rs and Norplant for 329.1 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding/spotting days with Implanon decreased from 33.5 in the first period to 19.0-21.5 da ys in the last year. Similarly, with Norplant, the median number of bleedin g/spotting days decreased from 34.5 to 18.0-23.0 days, respectively. The nu mber of bleeding/spotting episodes during year 1 was 2.0 per 90-day referen ce period with Implanon and 3.0 per period with Norplant (p <0.05 for perio ds 1-4). For the remaining 90-day periods, there was no statistical differe nce between the two groups. In general, there was less frequent bleeding wi th Implanon compared with Norplant, whereas the incidences of amenorrhea an d infrequent bleeding were higher with Implanon than with Norplant. The mea n overall incidence of prolonged bleeding fell markedly during the study, f rom 66.0% in reference period 1 to 27.3% in period 16 with Implanon and fro m 69.0% to 21.7% with Norplant, respectively. The most common adverse event s were related to disturbed bleeding patterns, which were also the major re asons for discontinuation (Implanon n = 8; Norplant n = 24). Normal menses returned in almost all subjects within 3 months after removal of the implan ts. Implanon was inserted in a mean time of 0.61 min and Norplant in 3.90 m in (p <0.001). Similarly, the mean time required to remove the implant was significantly shorter for Implanon than for Norplant (2.18 min vs 11.25 min , p <0001). The maximum time required for removal of the implant was 10 min for the Implanon group and 60 min for the Norplant group. In both groups, blood pressure and hemoglobin were not affected, whereas body weight tended to increase. It can be concluded that both contraceptive systems demonstra ted excellent contraceptive efficacy and were well tolerated. Compared with Norplant, there was less frequent bleeding with Implanon, whereas the inci dence of infrequent bleeding and amenorrhea was higher. Implanon was signif icantly quicker to insert and to remove than was the multiple capsule syste m. CONTRACEPTION 1999;60:1-8 (C) 1999 Elsevier Science Inc. All rights rese rved.