[Vaginal bleeding patterns and the regularity in use of Norplant]

To understand vaginal bleeding patterns and the regularity in use of Norplant, and find out the main cause of termination that Norplant users can not bear.

A total of 306 menstrual diaries of Norplant users for 5 years were analyzed. The analysis of bleeding patterns was carried out by using the reference period approach and followed the guidelings published by WHO.

The total number of vaginal bleeding days and the number of spotting days in the first reference periods were 36.6 days and 21.5 days, respectively. They were decreased obviously in the third reference period. The number of bleeding days was not obviously changed. The percentage of irregular bleeding was predominent in all of the bleeding patterns, 43.1%-57.6% usually. The percentage of prolonged bleeding was 13.4%-31.0%, secondly. The percentage of "normal" was only 33%. The number of bleeding days and the percentage of prolonged bleeding were more in bleeding termination group than in continuation group. The percentage of irregular bleeding was lower.

During the initial stage of use of Norplant the total number of vaginal bleeding days was increased, but decreased obviously after 6 months. This change was influenced by the number of spotting days. Irregular bleeding and prolonged bleeding were main types of the disturbance of menstrual cycles after use of Norplant, The main cause of termination was prolonged bleeding.