Progestogen-only Contraceptives and Vaginal Bleeding

More than 20 million women worldwide use progestogen-only methods of contraception. The most widely used method among them is the injectable depot-medroxyprogesterone acetate (DMPA) with some 13 million users. The only other progestogen-only injectable, norethisterone enantate, has fewer than one million users.

Other progestogen-only methods of contraception include the implantable Norplant, which is currently used by about six million women, and the intrauterine system Mirena which has about one million users. Both these methods release levonorgestrel. Other methods are becoming available such as Implanon, the single-rod implantable system delivering etonogestrel (first registered in Indonesia in 1998), and other injectable and implantable systems are under development.

Progestogen-only injectable and implantable methods have several features in common. On the positive side they are very effective, and the fact that they are long-lasting makes them easy to use. On the other hand, they cause disturbances in the normal bleeding pattern. For instance, after one year of use it was found that less than 10% of women who used DMPA and Mirena, and only 25% of users of Norplant, experienced regular monthly bleeding. Other users reported various patterns of bleeding ranging from no bleeding through infrequent bleeds to irregular, frequent and prolonged bleeding.

Women normally accept that use of a contraceptive method may involve making a trade-off between benefits and disadvantages. However, many women are not prepared to tolerate unpredictable, irregular or prolonged bleeding.

A wide range of treatments have been tried in order to overcome disturbances to the bleeding patterns of women who use progestin-only methods. Surveys in the 1980s and 1990s show that treatment regimens have included estrogens, combined oral contraceptives, nonsteroidal anti-inflammatory agents, vitamins, iron and anxiolytics. The use of a combined oral contraceptive may help to regularize the bleeding of Norplant users, but women may doubt the advantage of using two contraceptive methods at the same time and the use of a method containing estrogen negates the advantage of an estrogen-free progestogen method.

Clearly, alternative more effective ways need to be found to meet women's concerns over disturbance of their bleeding patterns. Amenorrhoea may be a more feasible goal than regular bleeding for the users of progestogen-only methods. However, in view of the concern of many women to have regular menstruation, further research will be needed to find out whether amenorrhoea would be an acceptable goal for women of different sociocultural backgrounds.

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