Prospective multicentre study comparing levonorgestrel implants with a combined contraceptive pill: final results

Norplant is a hormonal, long term method of contraception requiring the sub-dermal placement of six flexible capsules containing levonorgestrel in the inner aspect of the upper non-dominant arm. This open, prospective, multicentre, parallel group study, comparing the acceptability of Norplant and a combined pill, was originally designed to follow 700 subjects for five years, but was discontinued early. The main outcome criteria were duration of use and reason for discontinuation if appropriate. This final analysis, concerning the 364 subjects who used the implant and 307 subjects who used a gestodene/ethinyloestradiol combined pill, shows a statistically significantly higher (p<0.001) continuation rate amongst the implant users at 83.4 per cent compared to the pill users at 64.4 per cent at one year and this difference decreased only slightly by two years. The most common reasons for discontinuation by the end of the study were adverse events in both groups (menstrual and then mood changes in the implant group and mood changes and then headaches in the pill group). From the whole cohort the proportion which were 'very satisfied' were higher in the implant group (28.5 per cent compared to 14.6 per cent). This study confirms, in the UK, a high continuation rate for implant users similar to other countries as reported in the literature. If acceptability and continuation rates are similar in the none study setting, then a substantial number of women will seek removal of the implant and possible reinsertion five years after the time of initial high popularity (ie 1999). Doctors need to be prepared for this possible high level of activity.