Menstrual bleeding patterns in untreated women and with long-acting methods of contraception. Task Force on Long-Acting Systemic Agents for Fertility Regulation.

The bleeding patterns recorded by women using one of two new types of long-acting hormonal contraception, a levonorgestrel-releasing vaginal ring or a monthly injectable, have been compared with those in an untreated group and those experienced by women using either a combined oral contraceptive (OC) or depot-medroxyprogesterone acetate (DMPA). The frequency of bleeding was very similar between the combined pill users, the ring users and the untreated women, who all recorded an average of 3.2-3.3 bleeding/spotting episodes every 90 days. Monthly injectable users had slightly fewer episodes. Women using a monthly injectable or a vaginal ring had longer bleeding/spotting episodes (5 days) than combined pill users (4 days). However, the untreated women and DMPA users had the longest episodes, averaging 6 days. The median value of the within-woman mean length of bleeding-free intervals was 20.6 days among ring users, 22.3 days in the untreated group, 23.6 days among women given a combined OC or a monthly injectable, and 27.4 days in the DMPA group. Women using any of the long-acting methods had more variable bleeding patterns than untreated women or combined pill users. Over a year of method use, however, the lengths of the bleeding-free intervals recorded by vaginal ring and monthly injectable users became more predictable. It is concluded that these newer methods do not produce the marked bleeding disturbances seen with DMPA.