A multicentred phase III comparative study between single-implant containing 3-ketodesogestrel (Implanon®) and implants containing levonorgestrel (norplant®) II. Vaginal bleeding patterns

Abstract

A multicentred Phase III clinical trial was conducted in Indonesia to compare two implantable contraceptives i.e. a single implant contaimng 3-ketodesogestrel (Implanon®) and implants containing levonorgestrel(Norplanfl). Efficacy, acceptability and safety of both implants were reported in paper I. This paper reports the comparison of bleeding patterns. A total of899 women were randomly assigned to each implantable contraceptive The comparison of the bleeding patterns is made using a 90-day reference period approach according to WHO guidelines. A total of883 subjects contributed to reference period analysis. In the Implanon® group 415 subjects contributed to the firs, reference period and 271 to the 12* reference period. In the Norplant group those figures were 417 and 318 respectively. There were Jive subjects (1.1%) in the Implanon® group and 4 in the Norplant group (0.9%) discontinued during the study due to bleeding irregularities. One subject (0.2%) in the Implanon® group and none in the Norplant® group discontinued due to amenorrhea. The median number of heeding spotting days ranged over the first 12 reference periods from 2.0 to 14.0 for Implanon® and from 6 0 to 12 0 for Norplant®, For both groups, the majority of bleeding-spotting days were spotting days. In both groups the incidence of amenorrhea in reference period 3 was higher than in the previous reference periods. In reference periods 3 to 12 amenorrhea occurred statistically significantly more frequent in the Implanon® group compared to Norplant® group. Although the incindence of infrequent bleeding wav initially high (approximately 60% in reference period I). it decreased during the study to about 30% in reference period 3 while no ZinbothgT5 (eXCeptfr RPW) between groups Were observed. The incidences of frequent bleeding and prolonged bleeding were low in both groups.