Perimenopause represents a pivotal transition in a woman’s life, marked by a natural shift from regular menstrual cycles to anovulatory cycles, characterised by irregular and often excessive menstruation, culminating in permanent infertility [1]. This phase typically commences 2 to 8 years prior to menopause and concludes one year thereafter [2]. Abnormal uterine bleeding (AUB) is a prevalent gynaecological condition among peri-menopausal women. During this period, ovarian function declines gradually, leading to a decrease in estradiol levels, which may result in abnormal uterine bleeding. The prevalence of AUB ranges from 10% to 30% among women of childbearing age, escalating to up to 90% among peri-menopausal women. Although AUB is predominantly attributed to benign lesions, it can also emanate from malignant lesions, such as atypical endometrial hyperplasia or endometrial carcinoma [3]. In 2011, the International Federation of Gynecology and Obstetrics (FIGO) introduced a novel classification system for AUB, subsequently endorsed by the American Congress of Obstetrics and Gynecology (ACOG) in 2012. This system, referred to by the acronym PALM-COEIN (endometrial polyp, adenomyosis, leiomyoma, malignancy and hyperplasia, coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not yet classified), categorises AUB based on its suspected aetiology: polyp, adenomyosis, leiomyoma, malignancy and hyperplasia, coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not yet classified [4]. Consequently, peri-menopausal AUB can significantly impair the physical and mental health of affected women. Therefore, early detection and diagnosis are paramount for the management of endometrial malignancies. Currently, the primary clinical diagnostic techniques include transvaginal ultrasound, hysteroscopy, and diagnostic uterine curettage, with hysteroscopy and transvaginal ultrasound being the most frequently utilised ancillary examination methods [5]. Hysteroscopy is regarded as the gold standard in the diagnosis and treatment of female endometrial lesions [6]. Transvaginal ultrasound plays a crucial role in the diagnosis of AUB, offering a comprehensive assessment of the uterus and its surrounding structures. Nevertheless, the accuracy of transvaginal ultrasound in diagnosing uterine lesions is suboptimal, with inconsistent diagnostic criteria and repeatability. In contrast, hysteroscopy proves more efficacious than transvaginal ultrasound in diagnosing endometrial diseases, albeit with limitations such as high costs, reduced convenience, and lower patient tolerance [7]. The aim of this study was to evaluate the efficacy of transvaginal ultrasound and hysteroscopy in the etiological diagnosis of peri-menopausal AUB, thereby providing a scientific foundation for the early diagnosis and treatment of perimenopausal abnormal uterine haemorrhage.

During the peri-menopausal period, ovarian function diminishes progressively, leading to imbalances in estrogen and progesterone levels. This hormonal disruption can cause endometrial polyps, simple and complex endometrial hyperplasia, and in some instances, atypical hyperplasia and endometrial carcinoma. Consequently, a subset of peri-menopausal women may develop AUB, which significantly impacts their physical and psychological well-being and overall quality of life. Therefore, identifying the underlying cause promptly is imperative. The primary objective of evaluating AUB accurately is to diagnose the bleeding’s aetiology, facilitate the early detection of serious conditions such as endometrial atypical hyperplasia and cancer, and enable the implementation of suitable treatment strategies [17].

The diagnosis of peri-menopausal AUB relies on the patient’s history, gynaecological examination, and appropriate laboratory and imaging investigations, with the final pathological diagnosis serving as the gold standard. Transvaginal ultrasound has emerged as the preferred initial imaging modality for patients with AUB, owing to its excellent feasibility, cost-effectiveness, safety, non-invasiveness, and repeatability. It is particularly advantageous in the primary screening for the aetiology of AUB, capable of diagnosing structural causes of abnormal bleeding such as polyps, adenomyosis, leiomyomas, hyperplasia, and malignancy, as well as aiding in the diagnosis of ovulatory dysfunction [8]. Despite its strengths, the specificity and sensitivity of transvaginal ultrasound are limited, and it alone cannot definitively exclude organic causes of AUB [18]. Hysteroscopy, a minimally invasive technique, allows direct observation of the endometrium’s thickness and colour, the opening of the bilateral fallopian tubes, uterine angles, cavity shape, and cervical canal. It excels in detecting small lesions that transvaginal ultrasound may miss, and electroresection or curettage of lesions can enhance the sensitivity and accuracy of the aetiological diagnosis of AUB. Despite its growing popularity, hysteroscopy faces limitations in clinical practice, such as cost, technical complexity, invasiveness, and patient tolerance.

Wang et al. [19] demonstrated that combining transvaginal ultrasound, enhanced by the K-means clustering colour image segmentation algorithm, with hysteroscopy significantly increased diagnostic sensitivity. This study’s results, encompassing 176 peri-menopausal AUB patients, revealed 21 cases of normal endometrium, 42 of benign endometrial hyperplasia, 75 of endometrial polyp, 7 of endometrial carcinoma, 4 of adenomyosis, 6 of atypical endometrial hyperplasia, 19 of uterine leiomyoma, and 2 of other uterine lesions. In diagnosing AUB caused by endometrial polyps, the concordance rates for hysteroscopy and transvaginal ultrasound were 93.3% and 77.3%, respectively, with the difference being statistically significant ($\chi$${}^2$ = 7.670, p = 0.006), indicating hysteroscopy’s superior efficacy in detecting endometrial polyps. The concordance rates for diagnosing AUB caused by normal endometrium, uterine leiomyoma, malignant transformation of the endometrium, adenomyosis, atypical hyperplasia, benign hyperplasia, and other factors did not show a statistically significant difference between the two methods. This discrepancy from previous findings may be attributable to factors such as small sample size. In diagnosing peri-menopausal AUB, transvaginal ultrasound showed a sensitivity of 89.7%, a specificity of 66.7%, and a negative predictive value of 46.7%. Hysteroscopy demonstrated higher sensitivity, specificity, and negative predictive value of 94.8%, 76.2%, and 66.7%, respectively. The combined diagnostic approach yielded sensitivity and specificity rates of 97.4% and 81.0%, respectively, and a negative predictive value of 81.0%, surpassing the individual use of transvaginal ultrasound and hysteroscopy. These findings aligned with the research by Wang et al. [19]. The consistency between transvaginal ultrasound results and the pathological diagnosis was moderate (Kappa = 0.475), while hysteroscopy showed substantial consistency (Kappa = 0.669). The combined use of transvaginal ultrasound and hysteroscopy presented a higher consistency with the pathological diagnosis (Kappa = 0.784), suggesting that this combined approach offers superior diagnostic efficacy in the evaluation of peri-menopausal AUB.

In conclusion, according to the study of 176 women with AUB during perimenopause, we know thantransvaginal ultrasound and hysteroscopy possess significant diagnostic utility in identifying the aetiology of peri-menopausal AUB. Transvaginal ultrasound, being both safe and relatively cost-effective, offers considerable benefits in the initial screening for the causes of AUB. However, the potential for missed or incorrect diagnoses remains. Although hysteroscopy is more expensive and less convenient, its integration with pathological examination significantly enhances the detection rates of cancerous and precancerous lesions. The combined application of transvaginal ultrasound and hysteroscopy improves the diagnostic accuracy for endometrial lesions. Therefore, it is recommended that this combined approach be employed in the evaluation of peri-menopausal AUB patients to promptly identify the cause of AUB and initiate appropriate treatment.

The data that support the findings of this study are available from Second Affiliated Hospital of Xinjiang Medical University but restrictions apply to the availability of these data, which were used under license for the current study and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of Second Affiliated Hospital of Xinjiang Medical University.

BT: conceptualization, data curation, formal analysis, investigation, methodology, writing - original draft, writing - review & editing. QHZ: conception, funding acquisition, resources. Both authors contributed to editorial changes in the manuscript. Both authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work. Both authors read and approved the final manuscript.

Informed consent was obtained from all individual participants included in the study. The Ethics Committee of the Second Affiliated Hospital of Xinjiang Medical University granted approval for this study (Ethics Approval Number: KY2024032030).

We extend our sincere thanks to Changsheng Xu for his contribution the fomal analysis in this manuscript. We extend our sincere thanks to everyone who supported us in the preparation of this manuscript.

The study was funded by Natural Science Foundation of Xinjiang Uygur Autonomous Region (2023D01C122) and Department of Gynecology, Second Affiliated Hospital of Xinjiang Medical University, State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia (SKL-HIDCA-2022-GJ4) and Open topic of the Key Laboratory of Neurological Diseases in Xinjiang (XJDX1711-2260). And the “Tianshan Talents” medical and health high-level personnel training plan (TSYC202301B128).

The authors declare no conflict of interest.