Olav Meirik, M.D.
World Health Organization, Special Program of Research, Development, and Research Training in Human Reproduction
This presentation reported provisional final results from the International Collaborative Postmarketing Surveillance led by the World Health Organization Special Program for Research, Development, and Research Training in Human Reproduction, with Family Health International and the Population Council. The purpose of the surveillance was to study, over a 5-year period, major short- to medium-term side effects of Norplant that had not been identified in clinical trials.
The surveillance was based on a controlled concurrent cohort research design with a study population of women aged 18 to 40 at enrollment, and enrolled through a total of 32 family planning clinics in eight countries—Bangladesh, Chile, China, Colombia, Egypt, Indonesia, Sri Lanka, and Thailand. Index subjects were women choosing Norplant in those clinics, and controls age-matched by 5-year bands, who either chose intrauterine devices (IUDs) or sterilization. None had contraindications to Norplant or IUD use. The study population consisted of 7,977 Norplant acceptors (49.8%), 6,625 IUD acceptors (41.1%), and 1,419 sterilized women (8.9%), for a total of 16,021. The largest representation was from China: 6,114 participants, half of whom were Norplant acceptors.
The initial study objective was to have no more than 15 percent loss from enrollment, that is, a follow-up level of 85 percent. In fact, overall loss to follow-up over the course of the study was a much lower 3.6 percent: 0.1 percent in China, 7.6 percent in other Asian countries, 3.2 percent in Latin America, and 3.6 percent in Egypt. The study accumulated an average of approximately 4.8 calendar years of follow-up of IUD users, and 5 years of follow-up of both Norplant users and women who had been sterilized. The result was 78,000 woman-years of