International experience with NORPLANT and NORPLANT-2 contraceptives.

Experience encompassing more than 20,000 woman-years of use of NORPLANT capsules and 6,000 woman-years of trials of NORPLANT-2 rods is reviewed. Implant contraception repeatedly has been associated with low pregnancy rates and high continuation rates through five full years of use. Weight has proved to be a factor related to effectiveness. Women weighing less than 50 kg experienced cumulative five-year pregnancy rates well below 1 per 100, whereas the overall cumulative rate has been 3.5 per 100. Medical events reported during use that have led to discontinuation are analyzed from four large data sets.