Norplant

In this review of Norplant, the authors trace its historical development, explain its delivery system, and discuss clinical trials evaluating the method's efficacy and safety. Due to major problems associated with the use of long-term injectables, the Population Council began researching the use of subdermal capsules of Silastic that could serve as the basis for a long-term, reversible, steroidal contraceptive. After experimenting with several steroids, researchers settled on levonorgestrel, which by 1976 had become the most widely used progestogen in oral contraceptives. The traditional Norplant system consists of 6 Silastic capsules, each measuring 34 mm by 2.4 mm and containing 36 mg of levonorgestrel, which are inserted subdermally in the upper arm. The capsules are removed after 5 years (the article describes both the implantation and removal procedures). The Population Council has also developed a 2nd generation system known as Norplant-2. The authors discuss the pharmacokinetics and mode of action of the implant system, and survey the results of clinical trials performed in almost 30 countries. These studies indicate an overall cumulative 5-year pregnancy rate of 3.5/100. Fertility returns rapidly following removal of the capsules. None of the studies reports increased incidence of any particular problems in the pregnancies and infants conceived after Norplant use. Researchers have found a high degree of satisfaction with the system among Norplant users. There are, however, some side effects associated with Norplant use -- most notably, menstrual disturbances. Beneficial effects associated with Norplant use include protection against unwanted pregnancy and ectopic pregnancy. The authors conclude Norplant is an effective, safe, and reversible long-term contraceptive.