Overview of menstrual pathology
Pathological disturbances of the menstrual cycle are predominantly reflected in altered bleeding patterns now considered under the umbrella term of abnormal uterine bleeding (AUB).
In addition, onset of menarche can be both premature and delayed as can the final cessation of menses (discussed in Chapter 46).Abnormal uterine bleeding
Chronic AUB is defined as ‘bleeding from the uterine corpus that is abnormal in volume, regularity and/or timing that has been present for the majority of the last 6 months' (39, 40).
Normal bleeding patterns are those considered within the 595th percentiles (Table 40.2) (39, 40). For the parameter of volume, greater than 80 mL is considered abnormal. However, in clinical practice, objective measurement of loss is redundant, rather a more patient-centred approach is used to define HMB: ‘excessive menstrual blood loss which interferes with a woman's physical, social, emotional and/or material quality of life' (41).
Classification of abnormal uterine bleeding
A structured classification of the causes of AUB has been developed by the Federation International de Gynecologie et d'Obstetrique (FIGO), summarized by the acronym PALM COEIN (Table 40.3) (40).
PALM represents the structural and COEIN the non-structural causes of AUB. It is recommended that the term dysfunctional uterine bleeding (DUB) is discarded. ‘DUB' is usually encompassed by AUB-C,-O, or -E.
As well as standardizing nomenclature and definitions of normality, it is hoped that the AUB ‘PALM-COEIN' classification system will provide a structured approach to clinical assessment and diagnosis. By the discarding of Latin and Greek derivatives there may be demedicalization of menstrual dysfunction to empower women and decrease the taboos surrounding menstruation, thus reducing the barriers to effective care. Furthermore, by standardizing patient groups with respect to causation it will facilitate research and meta-analyses.
Table 40.2 Suggested normal limits for menstrual parameters
| Clinical parameter | Descriptive term | Normal limits (5-95th percentiles) |
| Frequency of menses (days) | Frequent Normal Infrequent | 38 |
| Regularity of menses, cycle to cycle (variation in days over 12 months) | Absent Regular Irregular | No bleeding Variation ± 2-20 days Variation >20 days |
| Duration of flow (days) | Prolonged Normal Shortened | >8.0 4.5-8.0 80 5-80 United Kingdom is estimated to be the fourth most common reason women are referred to gynaecological services (42). In those with unpredictable bleeding, there may be an ovulatory, iatrogenic, or ‘not otherwise classified’ cause or a structural abnormality such as a polyp or underlying malignancy; typically those with AUB-A, - L, -C, and -E have predictable HMB. General principles of management Specific abnormalities of the menstrual cycle and their management are covered in more detail in Chapter 41. The approach to a woman presenting with perturbation of the menstrual cycle should be patient centred and encompass her contraceptive and reproductive needs and well as reflecting comorbidities and secondary health promotion, particularly with respect to bone mineral density, smoking cessation, cervical screening, and breast examination/enquiry. Assessment An accurate history can often identify those with a likely AUB-C, -O, or I as an underlying cause. In particular, a potential coagulopathy may be identified by structured questioning in up to 90% of cases (43, 44). Contributors to AUB-C and -O often then require specific function tests such as to von Willebrand factor and thyroid function tests respectively if pathology is suspected. Imaging, selected histopathology, and direct visualization through hysteroscopy will allow diagnosis of a structural cause (‘PALM’) or AUB-N. Hysteroscopy in particular may have greater utility than ultrasound scanning in distinguishing between those with AUB-P and submucosal fibroids and offers opportunity for concurrent resection (45). The United Kingdom National Institute for Health and Care Excellence recommends endometrial sampling (outpatient or hysteroscopic) in those with persistent intermenstrual bleeding or age 45 years and older with treatment failure (41), but the Royal College of Obstetricians and Gynaecologists advises sampling those with treatment failure aged 40 years and older (46). With the rise in incidence of endometrial cancer, sampling should be considered on a case-by-case basis in younger women with risk factors for malignancy such as polycystic ovary syndrome, obesity, and type 2 diabetes. AUB-E remains a diagnosis of exclusion as tests of endometrial dysfunction remain the preserve of research studies and there is a current lack of effective biomarkers.Other investigations aside from imaging and selected endometrial sampling include assessment for anaemia. Tests such as measurement of thyroid function, gonadotropin and prolactin levels, coagulopathy studies, and testing for evidence of chlamydial infection (in those women with intermenstrual bleeding) should be restricted to women who present with relevant symptomatology. Treatment strategies For those women with AUB without an infective or a malignant cause, a conservative approach may be adopted with iron replacement for correction of anaemia if required. For those wishing for active treatment, this should be tailored depending on current and future fertility desires and comorbidities. Mefenamic acid and tranexamic acid are the only non-hormonal medical treatments currently available. For women who are not actively seeking pregnancy, the levonorgestrel-releasing intrauterine system (LNG-IUS) remains the first line of treatment (41). However a significant proportion will discontinue treatment either through lack of efficacy or undesirable side effects (47). Alternative hormonal treatments include the combined oral contraceptive pill, progestin-only pill, cyclical progestins, and GnRH analogues (41). For women with AUB and fibroids, myomectomy, uterine artery embolization, and medical management with selective progesterone receptor modulators offer preservation of future fertility potential.For those women for whom fertility is no longer required, surgical management may be offered and has higher overall patient satisfaction (48). This may be in the form of endometrial ablation (destruction of the endometrium) or hysterectomy. Hysterectomy remains the only definitive treatment for HMB but has higher risks compared to ablation. Therefore, the largest meta-analysis to date concludes that less high- risk surgical procedures should be offered as a first line if surgical intervention is considered (49).
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