Menorrhagia Heavy Periods
Professor David L Healy
The condition of heavy periods, or excessive menstrual bleeding, is a common health complaint of many women aged 30-50 years. Heavy periods or Menorrhagia is reported to be the complaint in 15% of women seeing their doctor and to be the reason leading to 50% of all hysterectomies of removal of the uterus.
The complaint of heavy periods is essentially only a problem in women of this century. Indeed, menstruation has become much more frequent only in the 20th Century. For example, throughout most of human history, menarche typically occurred around 16 years of age. In many societies, this served as a social signal for marriage shortly thereafter. In ancient societies, many teenagers did not survive the birth of their first child. If they did, our typical ancestor experienced about 50 periods before dying in her thirties.
By contrast, many 12-year olds will have their first menstrual period. The typical woman in a developed country has two births and perhaps 500 episodes of menstruation over a lifespan of 82 years. It is this order of magnitude increase in menstruation which leads to the likelihood of the development of diseases leading to heavy periods. Table 1 indicates a typical group of causes of heavy periods. The excellent studies by Scandinavian workers over several years have confirmed that normal menstrual blood loss has a mean volume of 30-40 mL (Fig.1). The range of normal menstrual blood loss is typically 10-80 mL. Most authorities would accept that regular menses in excess of a measured menstrual blood loss of 80 mL of bleed each month will inevitably lead to anaemia.
Figure 1. The distribution of menstrual blood loss in a population sample
Measured menstrual blood loss is a research technique. It extracts the haemoglobin from sanitary pads and tampons and measures the concentration with reference to a venous blood sample. Of course, this technique is not available for routine assessment when taking a history from a woman complaining of excessive menstrual bleeding. However, there have been studies which have examined the number and type of sanitary protection used for normal menstruation as well as for heavy periods.
Unfortunately, the number and type of sanitary protection is known to be a poor predictor of menstrual blood loss. Similarly, and equally disappointingly, the woman's own assessment of her menstrual blood loss is a poor predictor. Pictorial charts are only 55% predictive value of heavy periods. The presence of "menstrual clots" have been shown to be of no predictive value in estimating true menstrual blood loss.
Table 1 indicates the common causes of heavy periods. These are grouped as to the common causes of heavy periods from the uterus, the ovary and from other conditions. In particular, it should be emphasised that ovulatory dysfunctional uterine bleeding is probably the most common cause of heavy periods. Dysfunctional uterine bleeding (DUB) is a diagnosis of exclusion that would require some form of endometrial sampling for the diagnosis to be satisfactorily made.
Fibrinolysis is the physiological mechanism by which fibrin or blood clot is broken down or lysed. Research studies have clearly shown that fibrinolysis is normal in the human endometrium and that fibrinolytic activity is measurable in menstrual fluid. Plasminogen activator is an enzyme which activates plasminogen. This converts plasminogen to plasmin which breaks down fibrin. Plasminogen activator is normally present in the human endometrium.
Tranexamic acid inhibits endometrial plasminogen activator (Fig 2).
Figure 2. Endometrial plasminogen activator is excessive in patients withheavy periods. Tranexamic acid inhibits endometrial plasminogen activator.