Vaginal bleeding disturbances associated with the discontinuation of long-acting injectable contraceptives. From the World Health Organization Special Programme for Research, Development, and Research Training in Human Reproduction; Task Force on Long-acting Systemic Agents for the Regulation of Fertility.Br J Obstet Gynaecol. 1981 Mar; 88(3):317-21.BJ
A randomized comparative trial of 832 women receiving norethisterone oenanthate (NET-OEN) and 846 women receiving depot medroxyprogesterone acetate (DMPA) injections at 12 week intervals was conducted in 10 centers. The pregnancy rate with NET-OEN was significantly higher than with DMPA. The termination rate for amenorrhoea was substantially lowe with NET-OEN than DMPA, whereas the discontinuation rates for bleeding problems were similar with the two drugs. Analysis of bleeding patterns among continuing and discontinuing users suggests that women tolerated frequent bleeding episodes, but found prolonged bleeding or prolonged bleeding-free intervals unacceptable. Bleeding for more than 30 days during an injection interval and complete amenorrhoea for a whole injection interval were jointly associated with 43.7% of all terminations among NET-OEN users and 64.5% of all terminations among DMPA users. In future efforts to improve the acceptability of long-acting injectable contraceptives, more attention should be given to the control of prolonged amenorrhoea and prolonged bleeding.