The FIGO classification of causes of abnormal uterine bleeding

Malcolm G. Munro, MD, FRCS(c), FACOG Hilary O.D. Critchley, BSc (Hons), MB ChB (Hons), MD, FRCOG, FRANZCOG, FFSRH, FMedSci Ian S. Fraser, AO, MD, BSc (Hons), FRANZCOG, CREI, FRCOG, FFFP (Hon), DUa Ian Fraser is a Professor of Reproductive Medicine at the University of Sydney, Australia, and a Reproductive Endocrinology and Infertility Subspecialist at the Royal Prince Alfred Hospital, Sydney. He is a past President of the Royal Australian and New Zealand College of Obstetricians and Gynecologists, and is currently Honorary Secretary of the International Federation of Gynecology and Obstetrics (FIGO). He is a member of the International Committee for Contraception Research of the Population Council. Dr Fraser is an Honorary Life Member of the Australian Gynecological Endoscopy Society and the Fertility Society of Australia. He gained his initial medical and specialist training in Edinburgh and Oxford, UK, and now has a range of clinical and laboratory research interests within reproductive medicine—specifically in the fields of menstrual disorders, endometriosis, contraception, and menopause transition. Dr Fraser has specific current major research interests in terminologies, definitions, and mechanisms of abnormal uterine bleeding, in addition to endometrial function in endometriosis. He has been an author on over 400 original scientific articles in peer-reviewed journals. Over the past 5 years, it has become increasingly clear that there is considerable confusion regarding several aspects of the topic of abnormal uterine bleeding (AUB). Initially, attention was paid to the urgent incongruities of menstrual terminology and definitions at a major international workshop in Washington, USA, in February 2005 [1,2]. This workshop also addressed issues related to the underlying causes of abnormal bleeding—a topic that is not clearly dealt with in the existing literature. The development of a definitive classification of such causes was identified as an area requiring urgent attention. The intention was to develop a comprehensive and clinically relevant classification, which would be initially presented in simple form for clinical use and, thereafter, subdivided into more detailed categories for specialist and research needs. The first concept was outlined in Washington and then presented in a short textbook on AUB [3]. The development of this process was strongly supported throughout by the International Federation of Gynecology and Obstetrics (FIGO). The FIGO-approved classification (published in this issue of the journal [4]) meets the above criteria and should assist in providing a solid basis for the standardization of international research and clinical manuscripts addressing the diagnosis, pathogenesis, and management of AUB. It is recognized that, from time to time, new research will lead to a need for greater precision or modification of initial recommendations. Hence, the FIGO classification is regarded as a flexible “living” document that should undergo review and consideration for modification at regular intervals. It is suggested that discussion of the practical use and clarity of the classification should initially occur at 3-yearly intervals—in line with each FIGO World Congress. The classification is based on the “PALM-COEIN” mnemonic, which highlights the main structural (polyp; adenomyosis; leiomyoma; malignancy and hyperplasia) and non-structural (coagulopathy; ovulatory dysfunction; endometrial; iatrogenic; and not yet classified) groups of AUB causes. Each category can be subdivided, as required, for specialist and research needs, while the main categories will be sufficient for initial clinical care purposes. The subdivisions of each category can be made as complex as necessary for research comparisons and can be continually modified as research leads to clearer understanding of underlying molecular causes. A scoring system to enable very detailed research comparisons is described. Categories C, O, and E encompass those cases of AUB that were previously often incorporated into the diagnosis of “dysfunctional uterine bleeding” (a term that we recommend be discarded) [1,2]. Indeed, category E is now the “diagnosis of exclusion” because there is no clinically available test. Nevertheless, it should be recognized that endometrial causes may coexist with other definable entities such as leiomyomas, adenomyosis, and endometrial polyps. The classification presupposes the availability of certain basic technologies for investigation of the different causes: for example, transvaginal ultrasound scan; tissue biopsy; histology; and diagnostic hysteroscopy. More modern technologies will offer greater precision in settings in which they are available. Translation of questionnaires to define disorders of hemostasis (coagulopathies) can be made available in local languages. Questionnaires regarding hemoglobin, full blood count, and heavy menstrual bleeding should be available. We are privileged to have been entrusted with the task of developing a practical model from preliminary ideas from the original Washington workshop [1,2] and we are indebted to many colleagues for ongoing discussions (these colleagues are listed in the manuscript). It is our hope that journal editors will adopt a uniform approach—incorporating the features of the manuscript—to the classification of AUB causes.