Abnormal uterine bleeding (AUB) is one of the most frequent gynecological conditions among women of reproductive age, contributing significantly to outpatient visits and hospital admissions worldwide¹. It is defined as any deviation from the normal menstrual pattern in terms of frequency, regularity, duration, or volume of flow, in the absence of pregnancy². The International Federation of Gynecology and Obstetrics (FIGO) has standardized AUB classification using the PALM-COEIN system, which categorizes causes into structural (Polyp, Adenomyosis, Leiomyoma, Malignancy) and non-structural (Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, Not yet classified) groups³. Women aged 20–40 years represent the prime reproductive age group, when menstrual regularity is crucial for fertility, career, and psychosocial well-being⁴. AUB during these years can lead to anemia, fatigue, infertility, and psychological distress, adversely affecting quality of life and productivity⁵. The prevalence of AUB among reproductive-age women ranges between 9% and 30%, depending on the population studied and diagnostic criteria⁶. Structural causes such as leiomyoma and adenomyosis are more frequent in women in their 30s and 40s, whereas ovulatory dysfunction and endometrial causes predominate in younger reproductive women⁷. Ultrasound remains the first-line imaging modality for identifying structural abnormalities, particularly fibroids and adenomyosis⁸. Early evaluation and management of AUB are essential to prevent complications like chronic anemia and to ensure timely detection of endometrial pathology⁹. Our study focuses on evaluating the pattern, causes, and clinical presentation of AUB specifically in women aged 20–40 years — an age group that forms the core of reproductive health research yet remains underrepresented in region-specific epidemiological data¹⁰. Need for the Study Although AUB is extensively studied in adolescents and perimenopausal women, limited data are available focusing specifically on women aged 20–40 years — a group that represents the most active and fertile phase of life2. In this age group, menstrual regularity plays a vital role in fertility, hormonal balance, and psychological well-being3. Most published literature on AUB originates from Western or perimenopausal cohorts, with minimal representation of women in early and mid-reproductive years from Indian settings8. Socio-cultural factors and delayed health-seeking behavior further contribute to the under-diagnosis of AUB in this age group9. Understanding its pattern, etiology, and clinical presentation in women aged 20–40 years is therefore essential for improving diagnostic accuracy, guiding individualized therapy, and reducing long-term complications such as chronic anemia and infertility10. Hence, this study aims to evaluate the clinical spectrum and etiological profile of abnormal uterine bleeding specifically among women aged 20–40 years, thereby contributing region-specific data to strengthen reproductive health management strategies.

This observational study was conducted in the Department of Obstetrics and Gynecology, Subbaiah Institute of Medical Sciences, Shivamogga, over 6 months from March 2025 to August 2025. Women presenting with AUB,between 20-40 years Age were included, their demography, complaints, ultrasonography & Histopathology were done Source of data: Department of Obstetrics and Gynaecology, Subbaiah Institute of Medical Sciences, Shivamogga Study Design: observational study Period of collection of data: March 2025 to August 2025. Data collected included age, parity, Complaints, ultrasonography & Histopathological diagnosis.

Table 1: Age Distribution AGE No. of patients Percentage 21-25 14 5.5 % 26-30 31 12.5 % 31-35 89 35.5 % 35-40 116 46.5 % Table 2: Common Complaints Complaints Total no. Percentage HMB 110 44 % HMB + Irregular Cycles 73 29 % Irregular Cycles 55 22.5 % Prolonged Bleeding 9 3.5 % Intermenstrual spotting 3 1 % Table 3: Parity Parity Total no. Percentage Nulliparous 9 3.5 % 1-2 137 55 % >3 104 41.5 % Table 4: Ultrasonography Total no. Percentage Normal study 92 36.5 % Fibroid 63 25.5 % Adenomyosis 35 14 % Adenomyosis with Thick ET 25 10 % Thick ET 30 12 % Ovarian cyst 5 2 % Table 5: Histopathological Findings HPE Total no. Percentage Proliferative endometrium 13 43 % Secretory Endometrium 7 24% Disordered Proliferative Endometrium 6 20 % Hyperplasia without Atypia 4 13 % DISCUSSION Table 1 Study 21-25 26-30 31-35 36-40 <45 45-55 >55 Article 1 39.5% 33.5% 27% Article 3 68.7% 27.48% 3.79% Our study 5.5 % 12.5 % 35.5 % 46.5 % In Other Studies showed AUB is common in women <45 years. However we have further studied in detail, specific group from 20-40years, where we could find majority of cases of AUB is still found anytime from 20years onwards with maximum being between age group 36-40years. Table 2 Study Nulliparous 1-2 >3 Article 3 2.84% 31.69% 72.66% Our Study 3.5 % 55.5 % 41.5 % Our study showed 59% of AUB women having Parity of <3 whereas Nargis et.al. showed Parity of >3. Table 3 STUDY Menorrhagia Metrorrhagia Polymenorrhea Dysmenorrhea Post menopausal bleeding Menometrorrhagia Prolonged bleeding Article 1 52.08% 22.91% 25% 20.83% Article 5 32% 8% 12% 28% 20% Our Study 44% 22.5% 29% 3.5% Majority of Women included in our study presented with Menorrhagia(44%).Similar findings were reported by others too. Table 4 STUDY Normal study Polyp Adenomyosis Fibroid Malignancy Ovulatory dysfunction Endometrial Disorder Iatrogenic Not classified Article 1 4.10% 14.58% 52.08% 29.16% Article 2 16.53% 9.58% 45.73% 2.91% 35.96% 0.38% 1.31% 0.75% Article 3 4.81% 9% 57.39% 1.06% Article 5 38% 6% 14% 22% 4% Our Study 36.5% 14% 25.5% 2% 12% Ultrasonography done in our study showed No structural abnormality in majority of cases.Fibroid was most common Finding in all studies except in Jyotshna Sharma et al. where majority of abnormal Ultrasound finding was Hyperplastic Endometrium(22%). Table 5: HPE Findings STUDY Proliferative Endometrium Secretory Endometrium Atrophic Endometrium Endometritis Polyp Endometrial Hyperplasia Malignancy Article 1 6.25% 29.16% Article 3 62.03% 20.32% 2.13% 14.43% 1.06% Article 5 44% 20% 18% 8% 6% 4% Our Study 63% 24% 13% Our study & majority of other studies, showed Proliferative Endometrium as most common HPE report. Whereas Kalathuru Uhasai et al. showed Malignancy in 29.16% which was due to inclusion of Post-Menopausal age group.

AUB is common in all age groups from age 20 to Post Menopause with the most common structural cause being Fibroid uterus & endometrium in Proliferative Phase. However one must rule out Malignancy in Elderly age group. Author Contributions All authors have reviewed the final version to be published and agreed to be accountable for all aspects of the work. Concept and design: Dr Shivamurthy H M Acquisition, analysis, or interpretation of data: Dr Shivamurthy H M Drafting of the manuscript: Dr Arshiya, Dr Priyanka, Dr Madhu, Dr.Husena Gheewala,Dr.Rashmi Critical review of the manuscript for important intellectual content: Dr Shivamurthy HM Supervision: Dr Shivamurthy H M Disclosures Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. The Institutional Ethical Committee of Subbaiah Institute of Medical Sciences (IEC-SUIMS) issued approval IEC-SUIMS/12/2024-25. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work. Acknowledgements We extend our gratitude to the medical director, Dr. Nagendra S; the executive director, Dr. Latha R. Telang; the dean, Dr. Vinayaka G; and the principal, Dr. Siddalingappa CM, of Subbaiah Institute of Medical Sciences

1. Whitaker L, Critchley HOD. Abnormal uterine bleeding. Best Pract Res Clin Obstet Gynaecol. 2016;34:54–65. [Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC4970656/] 2. Kaunitz AM, Trolice MP. Abnormal uterine bleeding in reproductive-age women. JAMA. 2019;321(21):2151–2152. 3. Munro MG, Critchley HOD, Broder MS, Fraser IS; FIGO Working Group on Menstrual Disorders. FIGO classification system (PALM-COEIN) for causes of abnormal uterine bleeding in non-gravid women of reproductive age. Int J Gynaecol Obstet. 2011;113(1):3–13. 4. Tesfaye T, Yeshaneh A, Abuhay N, Abera M. Abnormal uterine bleeding and its associated factors among reproductive-age women attending public health facilities in Southern Ethiopia. BMC Womens Health. 2024;24:3128. [Available from: https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-024-03128-6] 5. Alharbi A, Alzahrani S, Alhazmi R, Alghamdi N. Management of abnormal uterine bleeding among reproductive age group women: a cross-sectional study. J Clin Med. 2024;13(23):7086. [Available from: https://www.mdpi.com/2077-0383/13/23/7086] 6. Kadir RA, Chi C. Abnormal uterine bleeding: a narrative review. Precision Medicine. 2021;1(1):4911. [Available from: https://pm.amegroups.org/article/view/4911/html] 7. Zhang J, Li Y, Wang J, et al. Therapeutic selection for abnormal uterine bleeding with ovulatory dysfunction: a cross-sectional study in Chinese women. Front Med. 2024;11:11812333. [Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11812333/] 8. Bhatla N, Suneja A. Abnormal uterine bleeding: The well-known and the unknown. Cureus. 2024;16(7):e11101194. [Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11101194/] 9. Kaunitz AM. Medical management of abnormal uterine bleeding in reproductive-age women. Obstet Gynecol Manag. 2013;25(11):130–137. [Available from: https://cdn.mdedge.com/files/s3fs-public/issues/articles/obgm0311130_kaunitz_0.pdf] 10. Sinha S, Pandey D, Singh A. Barriers to seeking consultation for abnormal uterine bleeding among reproductive-age women. BMC Womens Health. 2020;20(1):236. [Available from: https://bmcwomenshealth.biomedcentral.com/articles/10.1186/s12905-020-00986-8] 11. Uhasai K, Naik D, Deepti N. Efficacy of MRI over Ultrasound in Evaluation of Abnormal Uterine Bleeding with Histopathological Correlation. Cureus. 2023 May 4;15(5) – Article -1 12. Ni P, Wu M, Guan H, Yuan Y, Zhang L, Zhang F, Wei X, Li Y. Etiology distribution of abnormal uterine bleeding according to FIGO classification system: A combined study of ultrasound and histopathology. Journal of Obstetrics and Gynaecology Research. 2022 Jul;48(7):1913-20 -Article -2 13. Nargis N, Karim I, Sarwar KB. Abnormal uterine bleeding in perimenopausal age: different causes and its relation with histopathology. Bangladesh Journal of Medical Science. 2014 Mar 10;13(2):135-9 – Article-3 14. Kaur SB, Singh S, Singh A. Correlation of Body Mass Index with Endometrial Pathology in Perimenopausal Women with AUB: A Prospective Study. Journal of Mid-life Health. 2025 Jan 1;16(1):19-25 -Article-4 15. Sharma J, Tiwari S. Hysteroscopy in abnormal uterine bleeding vs ultrasonography and histopathology report in perimenopausal and postmenopausal women. J Nepal Med Assoc. 2016 Jul 1;55(203):26-8 – Article -5