Menorrhagia--a pragmatic approach to the understanding of causes and the need for investigations.

Menorrhagia is a symptom denoting excessively heavy menstrual bleeding. It is a complaint that is difficult to verify objectively in many cases, even with a detailed case history. Issues of perception and tolerance of symptoms are important in whether a patient presents to a doctor, and this varies considerably from one society to another. Research studies indicate that the upper limit of normal blood loss is between 60 and 80 ml/month. Above this level women tend to become progressively iron deficient. Hence, any development which may help the precision of this assessment is valuable, and several of these will be discussed. Causes of menorrhagia can be divided into three groups: (1) pelvic diseases, such as myomata and adenomyosis; (2) systemic disorders, such as coagulopathies and hypothyroidism; and (3) dysfunctional uterine bleeding--a diagnosis of exclusion. Investigations are mainly aimed at improving the precision of the underlying diagnosis, defining the severity of the condition and excluding anaemia. Hence, the most important investigations are a full blood count, a diagnostic hysteroscopy and endometrial sampling. In clinical practice, other specific investigations need only be carried out if there are unusual features in the history or examination, or if previous treatments have failed. In a research situation there have been numerous studies aimed at elucidation of the mechanisms of heavy bleeding and some of these will be reviewed.