ABSTRACT
BACKGROUND: In the field of endometriosis, several classification, staging and reporting systems have been developed. However, endometriosis classification, staging and reporting systems that have been published and validated for use in clinical practice have not been systematically reviewed up to now. OBJECTIVES: The aim of the current review is to provide a historical overview of these different systems based on an assessment of published studies. MATERIALS AND METHODS: A systematic Pubmed literature search was performed. Data were extracted and summarised. RESULTS: Twenty-two endometriosis classification, staging and reporting systems have been published between 1973 and 2021, each developed for specific and different purposes. There is still no international agreement on how to describe the disease. Studies evaluating different systems are summarised showing a discrepancy between the intended and the evaluated purpose, and a general lack of validation data confirming a correlation with pain symptoms or quality of life for any of the current systems. A few studies confirm the value of the Enzian system for surgical description of deep endometriosis. With regards to infertility, the endometriosis fertility index has been confirmed valid for its intended purpose. CONCLUSIONS: Of the 22 endometriosis classification, staging and reporting systems identified in this historical overview, only a few have been evaluated, in 46 studies, for the purpose for which they were developed. It can be concluded that there is no international agreement on how to describe endometriosis or how to classify it, and that most classification/staging systems show no or very little correlation with patient outcomes. WHAT IS NEW?: This overview of existing systems is a first step in working towards a universally accepted endometriosis classification.
ABSTRACT
BACKGROUND: Different classification systems have been developed for endometriosis, using different definitions for the disease, the different subtypes, symptoms and treatments. In addition, an International Glossary on Infertility and Fertility Care was published in 2017 by the International Committee for Monitoring Assisted Reproductive Technologies (ICMART) in collaboration with other organisations. An international working group convened over the development of a classification or descriptive system for endometriosis. As a basis for such system, a terminology for endometriosis was considered a condition sine qua non. OBJECTIVES: The aim of the current paper is to develop a set of terms and definitions on endometriosis that would be the basis for standardisation in disease description, classification and research. MATERIALS AND METHODS: The working group listed a number of terms relevant to be included in the terminology, documented currently used and published definitions, and discussed and adapted them until consensus was reached within the working group. Following stakeholder review, further terms were added, and definitions further clarified. Although definitions were collected through published literature, the final set of terms and definitions is to be considered consensus-based. After finalisation of the first draft, the members of the international societies and other stakeholders were consulted for feedback and comments, which led to further adaptations. RESULTS: A list of 49 terms and definitions in the field of endometriosis is presented, including a definition for endometriosis and its subtypes, different locations, interventions, symptoms and outcomes. Endometriosis is defined as a disease characterised by the presence of endometrium-like epithelium and/or stroma outside the endometrium and myometrium, usually with an associated inflammatory process. CONCLUSIONS: The current paper outlines a list of 49 terms and definitions in the field of endometriosis. The application of the defined terms aims to facilitate harmonisation in endometriosis research and clinical practice. Future research may require further refinement of the presented definitions. WHAT IS NEW?: A consensus based international terminology for endometriosis for clinical and research use.
ABSTRACT
STUDY QUESTION: Are novel circulating placental markers prokineticin-1 (PK-1), soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng) and placental growth factor (PlGF) associated with late miscarriage in asymptomatic first trimester pregnant women? SUMMARY ANSWER: Increased serum sFlt-1 or PlGF, but not sEng or PK-1, were significantly associated with reduced miscarriage risk after adjustment for age, BMI, gestational age, smoking and blood pressure. WHAT IS KNOWN ALREADY: Abnormal placental development is observed in two-thirds of miscarriages. Identifying women at high risk of late miscarriage could help diagnose potentially treatable causes of miscarriage such as infection, thrombosis or immunological disease. Recently, the circulating placental markers PK-1, sFlt-1, sEng and PlGF have been identified; however, it is not known if circulating levels of these markers are associated with late miscarriage. STUDY DESIGN, SIZE, DURATION: A single-centre observational cohort study with prospectively collected data was carried out at a tertiary care centre 2010-2012, in 993 asymptomatic pregnant women. Plasma PK-1, and serum sEng, sFlt-1 and PlGF were measured once in each patient during the antenatal booking visit, and pregnancy outcome was monitored prospectively. Less than 1% of patients were lost to follow-up. Multiples of median (MOM) levels were calculated to adjust for gestational age. PARTICIPANTS/MATERIALS, SETTING, METHODS: Nine-hundred and ninety-three asymptomatic pregnant women attending antenatal clinic for a routine booking antenatal appointment were recruited to the study, of whom 12 were lost to follow-up and excluded from analysis. Of the cohort, 50 of the remaining 981 women suffered late miscarriage. MAIN RESULTS AND THE ROLE OF CHANCE: Gestation-adjusted sEng, sFlt-1 and PlGF levels were 11% (P < 0.01), 36% (P < 0.001) and 30% (P < 0.001), respectively, lower in women who later suffered miscarriage compared with unaffected pregnancies, while PK-1 did not differ significantly. Logistic regression modelling suggested that increased sFlt-1 (odds ratio (OR) 0.15 95% confidence interval [0.08-0.26], P = 0.0001) and PlGF (OR 0.02 [0.01-0.05], P = 0.0001), but not sEng, were associated with reduced miscarriage risk after adjustment for age, BMI, gestational age, smoking and blood pressure. The combination of sFlt-1 and PlGF did not improve the diagnostic accuracy beyond the use of sFlt-1. LIMITATIONS, REASONS FOR CAUTION: First trimester levels of sFlt-1 and PlGF, but not sEng or PK-1, were associated with late miscarriage risk in asymptomatic women. However, a new prospective study is now required to investigate the utility of these markers to predict early (<10 weeks) and late miscarriage, as well as to predict other complications of pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: Our data suggest that circulating sFlt-1 and PlGF, but not sEng or PK-1, are independently associated with late miscarriage risk in asymptomatic pregnant women attending their antenatal visit. Therefore, sFlt-1 and PlGF may represent novel markers of placental viability. These data further our understanding of placental function, and have important potential implications for utilizing novel hormonal markers to detect adverse clinical outcomes during pregnancy. STUDY FUNDING/COMPETING INTERESTS: The authors have no competing interests. The Section of Investigative Medicine is funded by grants from the MRC, BBSRC, NIHR, an Integrative Mammalian Biology (IMB) Capacity Building Award, an FP7-HEALTH-2009-241592 EuroCHIP grant and is supported by the NIHR Imperial Biomedical Research Centre Funding Scheme. This project was funded by an NIHR grant (reference: CDF-2009-02-05). The following authors are also funded as follows: CNJ is supported by an NIHR Clinical Lectureship and AMS/ Wellcome Starter Grant for Clinical Lecturers. AA and ANC are supported by NIHR academic clinical lectureships. CI-E is supported by an Imperial College Healthcare NHS Trust Charity Research Fellowship. WSD is supported by an NIHR Career Development Fellowship. TRIAL REGISTRATION NUMBER: Q0406/80.
