Abnormal uterine bleeding (AUB) is one of the most common gynecological problems worldwide and may adversely affect physical health, quality of life, social activities, and emotional well-being [1,2]. AUB includes abnormalities in menstrual bleeding with respect to frequency, regularity, duration, or volume. Heavy menstrual bleeding may also contribute to iron deficiency and anemia [3]. The International Federation of Gynecology and Obstetrics (FIGO) introduced the PALM-COEIN classification to provide a standardized system for describing the causes of AUB [4]. The classification includes structural causes such as Polyp, Adenomyosis, Leiomyoma, and Malignancy and hyperplasia, represented by PALM, and non-structural causes such as Coagulopathy, Ovulatory dysfunction, Endometrial, Iatrogenic, and Not otherwise classified, represented by COEIN [4,5]. In India, AUB is also a frequent gynecological complaint, particularly among women in the perimenopausal age group. Indian studies have demonstrated considerable variation in the distribution of structural and non-structural causes of AUB [6,7]. The present study was designed to assess the clinical presentation and underlying etiological categories of AUB. AUB may present with different bleeding patterns, including heavy menstrual bleeding, intermenstrual bleeding, frequent menstrual bleeding, and irregular bleeding [3,5]. The underlying causes may be structural, such as polyps, adenomyosis, and leiomyoma, or non-structural, such as ovulatory and endometrial dysfunction [4,8]. The FIGO PALM-COEIN system provides a common terminology and framework for classifying these causes, thereby facilitating clinical evaluation, research, and communication among healthcare professionals [4,9]. In the present study, 100 patients were assessed according to age, clinical pattern of AUB, and PALM-COEIN etiological category. The present study was undertaken because identification of the underlying cause of AUB is essential for appropriate diagnosis and management. Although the clinical manifestation may be similar, the underlying pathology may differ considerably between patients. In particular, women in the perimenopausal age group may have structural lesions as well as endometrial or ovulatory abnormalities [6,10]. Determining the predominant clinical patterns and etiological categories in a given population can help in understanding the local disease profile and may assist clinicians in planning appropriate investigations. Therefore, this study was conducted to determine the age distribution, clinical pattern, and etiological causes of abnormal uterine bleeding according to the PALM-COEIN classification in the study population.

Study design and study population The present study was conducted among 100 patients presenting with abnormal uterine bleeding. The available study data included age distribution, clinical pattern of bleeding, and etiological classification according to the PALM-COEIN system. Age classification The study population was divided into four age groups: • 20–29 years • 30–39 years • 40–49 years • ≥50 years The number and percentage of patients in each age group were recorded. Clinical pattern of abnormal uterine bleeding The patients were categorized according to the clinical pattern of abnormal uterine bleeding recorded in the study. The reported categories included: • Menorrhagia • Metrorrhagia • Polymenorrhea • Menometrorrhagia • Hypomenorrhea The frequency and percentage of each clinical pattern were determined. PALM-COEIN classification The etiological causes of AUB were classified according to the FIGO PALM-COEIN system [4,5]. PALM – Structural causes P – Polyp (AUB-P): Abnormal uterine bleeding associated with endometrial or endocervical polyps. A – Adenomyosis (AUB-A): Abnormal uterine bleeding associated with adenomyosis. L – Leiomyoma (AUB-L): Abnormal uterine bleeding associated with uterine leiomyomas. M – Malignancy and hyperplasia (AUB-M): Abnormal uterine bleeding associated with endometrial hyperplasia or malignant pathology. COEIN – Non-structural causes C – Coagulopathy (AUB-C): Abnormal uterine bleeding associated with systemic disorders of hemostasis. O – Ovulatory dysfunction (AUB-O): Abnormal uterine bleeding resulting from disturbances in ovulation. E – Endometrial (AUB-E): Abnormal uterine bleeding attributed to abnormalities in local endometrial mechanisms of hemostasis in the absence of another identifiable cause. I – Iatrogenic (AUB-I): Abnormal uterine bleeding related to medications, devices, or other medical interventions. N – Not otherwise classified (AUB-N): Causes of AUB that do not fit into the other PALM-COEIN categories [4,5]. The PALM-COEIN system separates structural causes from non-structural causes and provides standardized terminology for clinical practice and research [4,9]. Data analysis The available data were analyzed descriptively. The results were expressed as frequency and percentage. As the total study population was 100 patients, the number of patients corresponded directly to the percentage for each category.

Age distribution A total of 100 patients with abnormal uterine bleeding were included in the analysis. The majority of patients belonged to the 40–49-year age group, accounting for 62% of the study population. This was followed by the 30–39-year age group with 24% as shown in Table 1. Table 1. Age distribution of patients with abnormal uterine bleeding Age Group No. of Patients (%) 20 – 29 years 4 (4 %) 30 – 39 years 24 (24 %) 40 – 49 years 62 (62 %) ≥ 50 years 10 (10 %) Total 100 (100 %) Clinical pattern of abnormal uterine bleeding Menorrhagia was the most common clinical pattern, occurring in 52% of patients. Metrorrhagia was observed in 22% of patients, followed by polymenorrhea in 14%, menometrorrhagia in 7%, hypomenorrhea in 1%, and another category recorded as polymenorrhea in 4%. Table 2. Clinical pattern of abnormal uterine bleeding Clinical Pattern No. of Patients (%) Menorrhagia 52 (52 %) Metrorrhagia 22 (22 %) Polymenorrhea 14 (14 %) Menometrorrhagia 7 (7 %) Hypomenorrhea 1 (1 %) Polymenorrhagia 4 (4 %) PALM-COEIN classification Among the PALM-COEIN categories, AUB-E was the most common etiological category, accounting for 28% of cases. AUB-L was the second most common category at 22%, followed by AUB-O at 18%. AUB-P accounted for 14% of cases, while AUB-A and AUB-M accounted for 8% and 6%, respectively. AUB-I and AUB-N were each observed in 2% of cases. No case was recorded under AUB-C in the supplied dataset. Table 3. Distribution of patients according to PALM-COEIN classification Etiology No. of Patients (%) AUB – E 28 (28 %) AUB – L 22 (22 %) AUB – O 18 (18 %) AUB – P 14 (14 %) AUB – A 8 (8 %) AUB – M 6 (6 %) AUB – I 2 (2 %) AUB – N 2 (2 %)

The present study evaluated the clinical pattern and etiological distribution of abnormal uterine bleeding among 100 patients. The majority of patients belonged to the 40–49-year age group, accounting for 62% of the study population. This finding indicates that AUB was particularly common among women approaching menopause in the present study. Changes in ovarian function and the increasing occurrence of structural uterine abnormalities during the perimenopausal period may contribute to abnormal bleeding [6,10]. The predominance of AUB among women in the 40–49-year age group is consistent with observations from Indian studies. Philip et al. evaluated 236 perimenopausal women with AUB and reported that leiomyoma was the predominant PALM category, while ovulatory dysfunction was an important COEIN cause [6]. The authors also demonstrated the usefulness of PALM-COEIN in clinical practice and clinicopathological assessment. In the present study, menorrhagia was the predominant clinical pattern, accounting for 52% of patients. Heavy menstrual bleeding is an important manifestation of AUB and may have a considerable impact on quality of life and may contribute to iron deficiency and anemia [2,3]. Contemporary FIGO-based recommendations emphasize characterization of bleeding according to frequency, duration, regularity, and flow volume before proceeding to assessment of possible causes [11]. Metrorrhagia was the second most frequent clinical pattern in the present study, accounting for 22% of cases. Other patterns included polymenorrhea, menometrorrhagia, and hypomenorrhea. The variation in bleeding patterns demonstrates the heterogeneous nature of AUB. FIGO developed standardized terminology because traditional terms for menstrual bleeding were often inconsistently defined and used [4,9]. According to the PALM-COEIN classification, AUB-E was the most common category in the present study, accounting for 28% of cases. Endometrial causes are classified under the non-structural COEIN component. They refer to disorders of local endometrial mechanisms that may result in abnormal bleeding in the absence of another identifiable cause [4,5]. The present finding differs from some Indian studies in which leiomyoma or ovulatory dysfunction was the predominant category. Such differences may be related to differences in age, patient selection, diagnostic methods, and criteria used to establish the underlying cause. AUB-L was the second most common category in the present study, accounting for 22% of cases. Leiomyoma is a common benign uterine lesion and is an important structural cause of AUB. In the Indian study by Philip et al., AUB-L accounted for 41.1% of cases and was the most common PALM category [6]. The lower proportion observed in the present study may reflect differences in the study population and diagnostic characteristics. AUB-O accounted for 18% of cases in the present study. Ovulatory dysfunction can result in abnormal bleeding because disturbances in ovulation lead to altered ovarian hormone patterns and irregular endometrial shedding [5,8]. Ovulatory dysfunction is particularly relevant in women with irregular menstrual cycles and during periods of reproductive hormonal transition. AUB-P accounted for 14% of cases, while AUB-A accounted for 8%. Polyps and adenomyosis are structural causes included in the PALM component of the FIGO system [4]. The presence of these categories in the present study demonstrates that both intrauterine lesions and myometrial abnormalities may contribute to AUB. AUB-M represented 6% of cases. Malignancy and hyperplasia are clinically important causes of abnormal uterine bleeding because persistent or abnormal bleeding may be an early manifestation of endometrial pathology. Therefore, appropriate evaluation of women with risk factors or persistent abnormal bleeding is important [2,11]. AUB-I and AUB-N were each recorded in 2% of patients. No patient was recorded under AUB-C in the supplied data. Although coagulopathy was not represented in the present dataset, it remains an important cause that should be considered in the appropriate clinical setting, particularly in patients with a history suggestive of an inherited or acquired bleeding disorder [5,11]. The findings of the present study demonstrate the usefulness of the PALM-COEIN system in organizing the different causes of AUB. The system was developed to overcome inconsistencies in terminology and to provide a classification that can be used in clinical practice, education, and research [4,9]. The 2018 FIGO revision further refined the systems for describing bleeding symptoms and classifying causes of AUB [5]. The distribution of etiological categories varies considerably between studies. In one Indian perimenopausal study, AUB-L was the most common category, followed by AUB-O [6]. In contrast, the present study identified AUB-E as the leading category, followed by AUB-L and AUB-O. These differences emphasize that the relative frequency of AUB causes may vary according to the characteristics of the study population and the diagnostic approach used [12-14]. The present study also demonstrates that the most common clinical presentation does not necessarily correspond to the most common etiological category. Although menorrhagia was the predominant bleeding pattern, AUB-E was the leading etiological category. This highlights the importance of evaluating both the bleeding pattern and the underlying cause rather than relying on clinical symptoms alone.

The present study showed that abnormal uterine bleeding was most frequently observed among women aged 40–49 years, who constituted 62% of the study population. Menorrhagia was the predominant clinical pattern, accounting for 52% of cases. According to the PALM-COEIN classification, AUB-E was the most common etiological category (28%), followed by AUB-L (22%) and AUB-O (18%). AUB-P, AUB-A, AUB-M, AUB-I, and AUB-N accounted for smaller proportions of cases. The findings indicate that both structural and non-structural causes contribute to AUB. The PALM-COEIN classification provides a systematic and standardized approach for identifying and documenting these causes. Its application may improve the clinical evaluation of women with AUB and help in selecting appropriate investigations and management strategies.

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