Post-menopausal bleeding represents a common clinical problem in primary care. Consultations for PMB with general practitioners are highest in women aged 50-59 years, at 14.3/1000 population over 1999-2000. (Further details of consultation rates and incidence by age group for all Continuous Morbidity Recording practices in Scotland between 1997 and 2000 are available on the SIGN website.) This data also indicates that consultation rates are rising, possibly related to increasing use of HRT.

3.1 When to refer

Traditionally, PMB has represented an absolute indication for gynaecological investigation. This is because it is difficult, if not impossible, to rule out endometrial cancer on clinical assessment alone. However, as discussed in section 2, the risk of cancer varies widely among different groups of women presenting with PMB.

Three considerations question the need for mandatory referral. First, the clinical assessment of PMB is complicated by irregular bleeding associated with the use of HRT. Second, there is little research evidence on the patterns of bleeding and whether, for example, light or 'one-off' bleeds should cause more alarm than heavier or recurrent bleeds - although intuitively either of the latter would be more likely to prompt referral. Third, there may be circumstances (e.g. patient preference) where any decision to refer may be deferred on mutual agreement.

General practitioners should take into account the pattern of bleeding, its relationship to the use of HRT and patient preferences when considering a referral. Concern from either general practitioner or patient about the possibility of PMB signalling endometrial cancer constitutes sufficient grounds for referral.²⁷ Evidence level 4

The risk of endometrial cancer in non-HRT users complaining of PMB and in HRT users experiencing abnormal bleeding is sufficient to recommend referring all patients for investigation.

3.2 Assessing abnormal bleeding in women using HRT

Abnormal bleeding in post-menopausal women receiving HRT can be caused by any of the following:

• poor compliance, especially related to omission of progestogens;
• poor gastrointestinal absorption (for oral preparations), e.g. due to gastroenteritis;
• drug interactions;
• coagulation defects;
• gynaecological disorders.

Clinical enquiry should aim to establish:

• whether the bleeding pattern is abnormal (as defined in section 1.3)
• any other related symptoms or contributory factors associated with endometrial cancer.

The following questions should be asked in the assessment of patients with abnormal bleeding on HRT: When does bleeding occur with respect to the oestrogen and the progestogen phase? (Women on sequential regimens should ideally not experience withdrawal bleeding before completion of the progestogen component of the preparation). How long does the bleeding last and how heavy is it? Was there a period of amenorrhoea before HRT was started? Is there a problem that suggests poor compliance? Is there a reason to suspect poor gastrointestinal absorption? Is the patient taking any other drugs?

3.3 Clinical examination

Women presenting with PMB require a pelvic examination at some stage during their assessment. If referred to a gynaecologist, an examination by the general practitioner is not always necessary. However, examination by a general practitioner or practice nurse can alter the course of clinical management if it expedites referral on grounds of raised suspicion of a malignancy (including cervical carcinoma) or highlights an obvious cause of bleeding (e.g. cervical polyps). This examination may also represent an opportunity to take a routine cervical smear if this is due for women within the National Screening Programme.

Women presenting with PMB should receive a pelvic examination at some stage during the course of their clinical assessment.

3.4 Continuation of HRT prior to investigation

Use of HRT generally leads to thickening of the endometrial lining, whereas continuous combined HRT and tibolone cause endometrial atrophy. There is uncertainty as to whether HRT should be stopped or not prior to investigation for PMB.

There is unlikely to be any problem in histological interpretation if the patient remains on HRT provided the pathologist is given details of the hormonal treatment. In addition the pathologist may be able to identify changes in the endometrium that are hormonally-induced and could explain the abnormal or unscheduled bleeding. Alternatively, by stopping HRT and inducing an oestrogen withdrawal bleed, tissue may theoretically be lost that should be assessed. In addition stopping HRT before investigation may transmit the wrong signals to patients regarding the risks of HRT.

For transvaginal ultrasonography the cut-off point of endometrial thickening beyond which further investigation is required can be adjusted for HRT use, although there is a greater risk of false positive results than if HRT were stopped.²⁸

Whether or not to continue HRT use prior to investigation may depend on the patient's wishes and how long she has to wait for investigations, but there is no specific reason for discontinuing it.

3.5 Effective communication between patients and practitioners

It is important that there is a clear flow of information between specialists, GPs and patients in order that the results of tests performed and their implications can be explained. Structured follow-up and advice on what to do in the event of recurrence should also be available.