ORGANUM
AUB is any bleeding disturbance that occurs during or between menstrual periods, or that is excessive, frequent or prolonged. This is the overarching term to describe any significant disturbance of menstruation or the menstrual cycle. FIGO has recently designed a classification system and precise terminologies for underlying causes of AUB - The figo AUB systems. These recommend that causes can be grouped under categories using the acronym PALM COEIN. The most common menstrual abnormalities are intermenstrual (often associated with PCB - post cotical bleeding) and heavy or irregular menstrual bleeding. The FIGO classification is a very useful and flexible system, which can easily be used for both initial training in understanding underlying causes and for application to more complex specialized or research classification.
FIGO recommendations on classification of causes underlying symptoms of abnormal uterine bleeding | |
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Structural lesions - PALM Polyps (endometrial, endocervical) Adenomyosis Leiomyoma (fibroids) Malignancy and hyperplasia | |
Non-structural causes - COEIN | |
Coagulopathies |
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Ovulatory dysfunction |
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Endometrial primary causes |
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Iatrogenic | A category including all causes from therapeutic or human interference:
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Not yet classified | Rare or novel causes which do not immediately or obviously fit into any of the other categories at this time. These may change with new research. Two examples of such conditions are uterine arteriovenous malformations, which can cause very heavy menstrual bleeding, or the novel diagnosis of 'isthomocele' (the lower segment 'niche' frequently found following C-section). |
IMB generally occurs between clearly defined, cyclical, regular mesnes. The bleeding may occur at the same time in each cycle of may be random. This symptom is typically associated with surface lesions of the genital tract, and these women may also experience PCB. Undiagnosed pregnancy-related bleeding, including ectopic pregnancy and hydatidiform molar disease may result in irregular bleeding mimicking IMB. In 1-2% of women, IMB may be physiological, with spotting occurring around the time of ovulation.
IMB is commonly associated with the use of hormonal contraception (when it is known as unscheduled or breakthrough bleeding), particularly the COCP, IUDs and use of progesterone-only methods, including the pills and implants.
In women with new onset of IMB, sexually transmitted infection of the cervix or vagina should be considered as a possible cause, especially Chlamydia. Less common cause are vaginitis (non-sexually transmitted), cervical ectropion, endometrial or cervical polyps, endometritis, adenomyosis, submucous myomas and sometimes cervical or endometrial cancers.
After a careful examination of the lower genital tract, the investigation of IMB should always exclude pregnancy and infection as a cause. Ensure that cervical screening is up to date, and if all these are negative, pelvic ultrasound or hysteroscopy may reveal an intrauterine cause.
PCB is a non-menstrual bleeding that occurs during or after sexual intercourse. The symptom is reported by around 6% of women per year. Causes of PCB include surface lesions of the genital tract; cervical or endometrial polyps; cervical, endometrial or vaginal (rare) cancer; and trauma. PCB occurs in 1%-39% of women with cervical cancer, and if there is a history of recurrent PCB, with or without IMB, colposcopy examination of the cervix is recommended even if the Pap Smear is normal.
Vaginal bleeding that occurs more than 1 year after the last natural menstrual period is known as postmenopausal bleeding. Although it is not the commonest cause of this symptom, the possibility of carcinoma of the body of the uterus should be considered, and an assessment of the endometrium is advised for all women, whether with diagnostic hysteroscopy and endometrial biopsy or with a high-quality transvaginal ultrasound measurement of endometrial thickness and appearance. When the endometrium is measured at less than 3mm, significant endometrial pathology is very unlikely.
Other causes of PMB include other benign and malignant tumours of the genital tract, infection and postmenopausal atrophic vaginitis. Stimulation of the endometrium by exogenous (or endogenous) oestrogen via hormone replacement therapy (HRT) or oestrogen from ovarian tumours should be considered.