Although heavy menstrual bleeding (HMB) or menorrhagia has been defined as the passage of over 80mls of blood in each menstrual cycle, due to the non practicability of measuring blood flow during the menstrual period, HMB can be defined as the complaint of recurrent or cyclical excessive menstrual blood loss over several consecutive menstrual cycles. Systematic assessment of menstrual blood loss however suggests that over 40% of women who complain of HMB have normal menstrual flow. Symptoms that strongly correlate with the presence of HMB, include a history of a consistent increase in the number of sanitary pads used over time, a history of passage of blood clots, a history of flooding of the under wears with blood and in severe cases, history of symptoms suggestive of complications of excessive blood loss such as dizziness, weakness and or fainting attacks during or immediately after the menstrual period.

Prolonged menstrual bleeding which is defined as the occurence of menstrual flow lasting more than 8 days is often a feature of HMB. Although, most cases of HMB occur in the context of a regular or ovulatory cycle, excessive menstrual flow alternating with scanty periods may be seen in anovulatory or irregular menstrual cycles e.g. women with anovulatory disorders such as PCOS and women at the extreme of the reproductive age groups i.e young women that recently commenced menstruation and older women approaching menopause. The increased presentation of HMB in recent years have been associated with a social and cultural change that encourage women to keep a very small family size and many others opting against having children, hence ensuring women are experiencing more menstrual cycles in current time than in previous generations. Interestingly, nulliparity, infertility and delayed first conception are common risk factors of many of the causes of HMB. With HMB being a common cause of anaemia, fatigue, weakness, and a significant cause of absence from work not to talk of its contribution as the commonest cause of hysterectomy worldwide, what then are the causes of HMB?



HMB is often caused by a variety of gynaecological, endocrinological, oncological and haematological disorders. Ways by which some of these disorders may increse the menstrual blood loss include:

1.  Increasing the surface area of the endometrial lining of the uterus, thereby increasing the area from which bleeding occurs within the uterus. Examples include endometrial polyps and submucous fibroids.

2.  Increasing the amount of blood that normally flows into the uterus. E.g. endometrial cancer, endometrial hyperplasia, adenomyosis and huge uterine fibroids.

3.  Preventing the normal process of blood clotting necessary to stop excessive blood loss during menstruation. E.g. Von willebrand disease and other bleeding disorders.

4.  By a combination of any of the above. e.g. uterine fibroids, adenomyosis and endometrial cancer may increase both the surface area of the endomterium as well as the amount of blood flow into the uterus. 

Unarguably in our environment and most of Africa, uterine fibroids remains the commonest cause of HMB. This may be because uterine fibroids are associated with the black or african race, among which the highest prevalence is found in the world. Not so in other parts of the World, where in about 50% of cases of HMB, no disorder is found despite appropriate investigations. This historically has been named ‘dysfunctional uterine bleeding’ (DUB). Various names such as ‘bleeding of endometrial origin’ (BEO) and unexplained menorrhagia, have been coined to replace this old term, but for the purpose of our discussion, we will stick with the use of DUB. Sugested possible causes of DUB include, the presence of abnormal prostaglandin production in the endometrium of women with HMB and or the abnormal development of some blood vessels within these women’s endometrium. Other than DUB, below is a list of some of the common causes of HMB:


1.  Uterine fibroids

2.  Adenomyosis

3.  Endometrial Polyps

4.  PID

5.  Endometrial hyperplasia

6.  Endometrial cancer

7.  Cervical cancer


Some medications or drugs that can cause prolonged and heavy menstrual bleeding include

1.  Progesterone only pills

2.  Anticoagulants

3.  IUCD


These are medical disorders present in other parts of the body other than the womb or the uterus that can result in HMB. They include:

1.  Hypothyroidism

2.  Bleeding disorders such as

1)  Von Willebrand’s disease.

2)  Idiopathic thrombocytopaenia purpura

3)  Factor V, VII, X and XI deficiency