Contraception. 1993 Aug;48(2):120-32. doi: 10.1016/0010-7824(93)90003-p.
The subdermal implant NORPLANT II contraceptive was studied for its safety, efficacy and acceptability over a period of 5 years of use in a phase III multicentre clinical trial. A total of 1,466 women were observed for 52,849 women-months of use. Only four pregnancies were reported during the study period, giving a method failure rate of 0.8 per 100 users at 5 years of use. The continuation rates were 61.4, 49.0 and 42.1 per 100 users at 3, 4 and 5 years of use, respectively. The majority of the discontinuations were due to bleeding irregularities which accounted for 22.2, 26.3 and 28.5 per 100 users at 3, 4 and 5 years of use, respectively. The next common reason was planning pregnancy which was observed mainly in women having one child. The discontinuations due to infection, expulsion or displacement of device were very low (0.2-0.3 per 100 users). Due to vigorous efforts made by the centers to follow the subjects, the lost-to-follow-up rate was very low (1.6% at 5 yr).
皮下植入式诺普兰II型避孕器在一项III期多中心临床试验中进行了为期5年的安全性、有效性和可接受性研究。共观察了1466名女性，累计使用时间达52849女性-月。研究期间仅报告了4例妊娠，5年使用期时每100名使用者的方法失败率为0.8。在使用3年、4年和5年时，每100名使用者的续用率分别为61.4、49.0和42.1。大多数停用情况是由于出血不规律，在使用3年、4年和5年时，每100名使用者中分别占22.2、26.3和28.5。其次常见的原因是计划怀孕，主要发生在已有一个孩子的女性中。因感染、装置排出或移位导致的停用率非常低（每100名使用者0.2 - 0.3）。由于各中心大力追踪受试者，失访率非常低（5年时为1.6%）。
