Normal menstruation refers to the bleeding from the endometrium that occurs with ovulatory cycles, typically lasting no more than five days. The bleeding can vary in intensity, sometimes being heavier or lighter than usual, and it may happen regularly or sporadically. 1-4According to the International Federation of Gynecology and Obstetrics (FIGO), Abnormal Uterine Bleeding (AUB) is characterized by changes in volume, regularity, or timing that persist for six months or more. AUB is one of the most common issues seen in gynecological outpatient settings. The FIGO group has categorized the different causes of AUB into structural or organic lesions and non-structural factors. 4-9Endometrial biopsy, followed by histopathological analysis, remains the gold standard for diagnosing the various causes of AUB, although interpreting these results can be quite challenging for pathologists. 1-9 Additionally, research has shown that endometrial hyperplasia and endometrial carcinoma can also be among the many causes of AUB. This study aims to evaluate the histopathological patterns of endometrial changes associated with AUB.

Objectives of the study:

1. To study the histopathological array of endometrial changes in AUB patients
2. To correlate these endometrial changes in AUB with various age groups

This retrospective observational study was conducted using archived histopathological records of endometrial biopsies received from January 2018 to December 2022. A total of 90 cases with AUB were retrieved from the pathology archives and analyzed.

Inclusion Criteria

All cases of endometrial biopsies submitted for histopathological examination with a clinical diagnosis of abnormal uterine bleeding were included in the study.

Exclusion Criteria

Patients diagnosed with uterine leiomyomas, cervical or vaginal pathology, and systemic conditions such as hypothyroidism, coagulation disorders, or other systemic diseases contributing to AUB were excluded. Cases with incomplete documentation, missing histopathological slides, or records that could not be retrieved due to archival limitations were also excluded from the study.

The relevant demographic and clinical data were extracted from the histopathology requisition forms, and microscopic findings were reviewed from the histopathological reports. The endometrial tissue samples were assessed for various histomorphological patterns, and cases were categorized according to reproductive status: reproductive (18–40 years), perimenopausal (41–50 years), and postmenopausal (>50 years).

Statistical Analysis

Descriptive statistical methods were employed for data analysis. The frequency and percentage distribution of histopathological findings across different age groups were calculated. Data analysis was performed using standard 

Table 1- Age wise distribution of endometrial biopsies in AUB

A total of 90 cases were included in the study, with their ages distributed across six groups. The largest proportion belonged to the 41–50 years age group (40%), followed by the 31–40 years group (32.22%). The younger group of 21–30 years constituted 12.22%, while the 51–60 and 61–70 age groups accounted for 6.67% and 7.78%, respectively. Only 1.11% of women were aged above 71 years. The mean age of the participants was approximately 42.1 years, indicating a predominance of middle-aged individuals in the study population.

Table2: Distribution of histomorphological pattern of endometrium

Among the 90 cases studied, the most commonly observed endometrial pattern was the proliferative phase, noted in 33 cases (36.7%), followed by endometrial hyperplasia without atypia, seen in 23 cases (25.6%). Endometrial polyps were identified in 8 cases (8.9%), while endometrial carcinoma was diagnosed in 5 cases (5.6%), highlighting a small yet significant occurrence of malignancy. Secretory phase endometrium accounted for 6 cases (6.7%), and various other findings such as menstrual endometrium, decidualized endometrium, pill endometrium, and disordered proliferative patterns were present in lower frequencies. Rare findings like granulomatous lesions, chronic endometritis, and infected decidual tissue were seen in isolated cases.

Table 3: Age group distribution in AUB cases

In the study AUB cases of 90 individuals, the majority belonged to the reproductive age group (18–40 years), comprising 40 cases (44.4%). This was followed closely by the perimenopausal group (41–50 years) with 36 cases (40%), while the postmenopausal group (>50 years) constituted 14 cases (15.6%).

Table 4: Age-wise distribution of histomorphological patterns of endometrium

The table presents the distribution of various endometrial changes across three different age groups: Reproductive (18–40), Perimenopausal (41–50), and Postmenopausal (>50). It shows a broad spectrum of endometrial conditions, including the proliferative and secretory phases, different types of endometrial hyperplasia, polyps, and carcinoma. The majority of cases in the reproductive age group (18–40) are in the proliferative phase, with 14 cases, followed by endometrial hyperplasia without atypia (6 cases) and endometrial polyps (5 cases). In the perimenopausal group (41–50), the proliferative phase is the most common, with 16 cases, and a significant number of cases of endometrial hyperplasia without atypia (13 cases) are observed. The postmenopausal group (>50) is marked by a lower frequency of changes, with endometrial carcinoma emerging as the most notable condition, occurring in 4 cases.

Abnormal uterine bleeding (AUB) is a common gynecological issue with diverse causes, from benign to cancerous. Diagnosing AUB requires careful investigation due to its varied presentations. Histopathological examination of the endometrium is crucial, revealing changes like hyperplasia or carcinoma.^1-5

In the present study, the highest number of endometrial biopsies for AUB was performed on women aged 41-50 years (40%), followed by the 31-40 year group (32.22%). This trend, with a peak in the perimenopausal age, aligns with findings from Anitha et al. (2021) and suggests the clinical significance of this period due to hormonal changes and increased risk of endometrial pathologies necessitating biopsy for diagnosis and management. However, this contrasts with studies by Shinde et al.¹⁰ and Bolde et al.,¹¹ which reported higher AUB incidence in younger age groups, highlighting potential variations across different populations.

The lower biopsy rates in younger women (21-30 years) in our study might reflect a tendency towards medical management for hormonally-related AUB, as suggested by ACOG¹² guidelines. Similarly, the decrease in biopsies in older postmenopausal women, despite some studies indicating higher AUB prevalence, could point to differing referral practices or biopsy thresholds in this cohort. These inter-study variations underscore the influence of population demographics, geographical factors, and clinical protocols on the age distribution of endometrial biopsies performed for abnormal uterine bleeding.

The current study reveals the histomorphological patterns of the endometrium in AUB patients, with proliferative phase being the most common

(36.7%), followed by endometrial hyperplasia without atypia (25.6%) and endometrial polyps (8.9%). This distribution shows both similarities and differences when compared to other studies. Prathipaa R⁵ found hyperplasia more prevalent, and Vani BS et al,⁶ reported a higher incidence of hyperplasia and inflammation, our data highlights the proliferative phase as the most frequent. However, the significant presence of endometrial hyperplasia aligns with findings from Roopmala et al.⁷ and Anitha et al.,⁸ emphasizing its role in AUB.

The occurrence of endometrial polyps (8.9%) is consistent with Doraiswami et al..¹³ Furthermore, the detection of endometrial carcinoma (5.6%) underscores the importance of biopsy in identifying potential malignancies, as also noted by Al-Nuaim et al.¹⁴ in older women. The presence of pregnancy-related findings, though infrequent, indicates the diverse etiologies of AUB. Overall, the observed histomorphological patterns reflect the complex interplay of hormonal influences and pathological processes underlying abnormal uterine bleeding.

We observed that the majority of endometrial biopsies for AUB in this cohort were performed on women in the reproductive (18-40 years, 44.4%) and perimenopausal (41-50 years, 40.0%) age groups, with a smaller proportion in postmenopausal women (>50 years, 15.6%). This distribution is consistent with several studies, such as Abdullah LS et al⁹ and Muzaffar et al.,¹⁵ which also found a higher prevalence of AUB requiring investigation in the reproductive age. However, some studies, like Dangal et al,¹⁶ reported a greater frequency in the perimenopausal period, highlighting potential variations across populations and healthcare settings.

The significant representation of both reproductive and perimenopausal age groups in our data underscores the importance of considering endometrial pathology across a wide age range in women with AUB. While the reproductive years are often associated with hormonal imbalances, the perimenopause carries an increased risk of endometrial hyperplasia and carcinoma, necessitating thorough evaluation. The smaller percentage in postmenopausal women, though still clinically relevant as it often warrants investigation for malignancy, suggests a different pattern of AUB presentation or referral in this specific cohort compared to studies focusing primarily on older women.¹⁴

Analysing the age-wise distribution of various endometrial changes in AUB cases. Proliferative phase endometrium was the most common finding across all age groups, with the highest number in the perimenopausal group (16 cases). Endometrial hyperplasia without atypia also showed a significant presence, particularly in the perimenopausal group (13 cases), followed by the reproductive group (6 cases). Endometrial polyps were more frequent in the reproductive age group (5 cases). Notably, endometrial carcinoma was predominantly observed in the postmenopausal group (4 cases), with a single case in the perimenopausal group. Atrophic endometrium was exclusively seen in the postmenopausal group.

Table 5: Comparison of Age-wise Endometrial Changes in AUB with Various Studies

Comparing these findings with other studies reveals age-related patterns in endometrial pathologies associated with AUB. The increased prevalence of endometrial hyperplasia without atypia in the perimenopausal group aligns with the hormonal fluctuations characteristic of this period, as suggested by studies focusing on this age range.¹⁴ The higher incidence of endometrial carcinoma in postmenopausal women is a well-established finding, consistent with the elevated risk of endometrial malignancy with advancing age.^14,17,18 The occurrence of proliferative phase endometrium as the most frequent finding across age groups could indicate that many AUB cases, particularly in the reproductive years, are related to ovulatory cycles and hormonal variations, a point also highlighted in studies examining younger AUB populations.^10,19,20,21

The distribution of endometrial polyps, with a higher frequency in the reproductive age group, is also consistent with existing literature indicating polyps as a common cause of AUB in younger women.¹³ The presence of pregnancy-related changes like decidualized endometrium, products of conception exclusively in the reproductive age group is expected. The relatively low numbers of other specific endometrial changes across age groups suggest their less frequent association with AUB in this particular cohort. Overall, Table 4 provides a valuable age-stratified perspective on the histomorphological patterns of endometrium in AUB, largely corroborating established associations between age and specific endometrial pathologies while also highlighting the heterogeneity of AUB etiology across different life stages.

Histopathological examination of endometrial biopsies is crucial for diagnosing abnormal uterine bleeding (AUB), revealing diverse patterns across age groups. Proliferative phase was most frequent overall, but endometrial hyperplasia without atypia was prominent in perimenopausal women, highlighting a risk factor for malignancy. Endometrial carcinoma was more common postmenopausally. The age-wise distribution shows varying lesion prevalence, with polyps in reproductive years and atrophy/carcinoma in older women. This underscores the age-dependent nature of AUB etiologies. Therefore, endometrial biopsy and histopathological analysis are vital for tailored diagnosis and management of AUB at all life stages.

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