Tackling the Problem of Endometrial Bleeding

Long-acting progestogen-only contraceptives are safe and very effective. Currently, more than 20 million women use long-acting progestogen-only methods such as depot-medroxyproges-terone acetate (DMPA) and Norplant. However, one drawback of these contraceptives is that they cause unpredictable vaginal bleeding (from the endometrium—the inner lining of the uterus) in a majority of women. For many, the bleeding is slight (with no risk of it causing anaemia), but its prolonged duration and unpredictability deter many women from using or continuing to use these contraceptives.

Effective counselling of a potential user of a progestogen-only method can help in preparing her both for the absence of menstruation and for the possibility of irregular endometrial bleeding. Research shows that women who are given information about what will happen and are reassured that it is a common side-effect are much more likely to continue using the method. Indeed, with some progestogen-only methods they find that bleeding disturbances tend to decline after a year or more of use.

Endometrial bleeding that is induced by the use of progestogens can be treated, but current treatments are of limited effectiveness. Thus there is considerable interest in finding both a treatment that works and a way to avoid the bleeding in the first place. To do this, a much better understanding is needed of the biological mechanisms that cause bleeding from the endometrium.

Dealing with the issue of endometrial bleeding in connection with the use of a contraceptive method involves far more than dealing with a physiological event. The way that women react to unpredictable bleeding, or indeed to amenorrhoea—the complete absence of menstrual bleeding—affects their attitude to the contraceptive method that causes it. Service providers and researchers need to be aware of the perceptions that women, and the communities they belong to, have of menstruation and of non-menstrual bleeding.

Even when we look at the specific event of endometrial bleeding induced by progestogen, much more knowledge is needed on how it actually happens. Endometrial bleeding induced by progestogens is not menstruation, although there are some similarities between the two processes, so it is important to see precisely what happens to an endometrium that is exposed to progestogens and that begins to bleed as a result. At the same time, our knowledge of what happens during menstruation is also progressing, and research in this area is helping with the development of contraceptive methods that do not cause women undue inconvenience.

In May 1999 the Programme and the US National Institute of Child Health and Human Development (NICHD) co-sponsored a meeting entitled "Steroids and endometrial breakthrough bleeding" at Monash University, Clayton, Australia. Participants in the meeting were leading scientists in this field. The proceedings of this meeting are to be published as a supplement of the journal Human reproduction in 2000. This issue of Progress presents some of the recent advances in the area of endometrial bleeding discussed at this meeting and gives an insight into the mechanisms of both natural menstruation and progestogen-induced bleeding.

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