Abnormal uterine bleeding (AUB) is a common gynaecological complaint defined as uterine bleeding from the uterine corpus that is not normal menstruation when assessed on the basis of quantity, quality, duration or frequency [1]. May happen at any time in the reproductive, perimenopausal or postmenopausal period and can negatively impact physical functioning, emotional health, work productivity and quality of life [2]. As many as 1/3 of women may develop AUB at some point in life, with a peak incidence around the time of menarche and perimenopause [3]. The PALM–COEIN classification was established by the International Federation of Gynecology and Obstetrics to have a uniform approach to the etiology of AUB. Non-structural causes include coagulopathy, ovulatory dysfunction, endometrial disorders, iatrogenic causes, and other causes, whereas structural causes include polyps, adenomyosis, leiomyoma/malignancy, and hyperplasia [4]. This classification helps in systematic clinical assessment and enhances communication among clinicians, researchers, and pathologists [5]. While most cases of AUB are related to benign or hormonal causes, however, if women are aged 45 years or older or if women are younger and have persistent bleeding or other risk factors, such as obesity, chronic anovulation, diabetes mellitus, hypertension, polycystic ovarian syndrome, or prolonged exposure to unopposed oestrogen, then endometrial hyperplasia or malignancy should be ruled out [6]. Histopathological examination of the endometrial tissue is thus a key part of the work-up in the appropriate patient with AUB [7]. It is important to get enough tissue samples as the only diagnosis may be delayed, additional procedures may be necessary, health care expenses may be higher, and the patient's anxiety may be greater if they don't get enough tissue from the procedure [8].

The endometrial biopsy, which is conventionally performed by dilatation and curettage (D&C), is a well-established diagnostic procedure and has been used for a long time to obtain endometrial tissue [9]. Typically, however, a cervical dilatation, anaesthesia, operating theatre and observation are required for D&C, which takes more time. It can also have a link to pain, haemorrhaging, infection, cervical trauma, uterine puncture and side-effects of anaesthesia [10]. Furthermore, conventional D&C is often carried out in this manner without any visualisation of the endometrium, and focal abnormalities like polyps or hyperplastic lesions can be missed occasionally if D&C is not performed in combination with hysteroscopy [11]. The Pipelle endometrial sampling is a thin and flexible, disposable suction device which allows endometrial sampling in the outpatient without cervical dilatation or under general anaesthetic [12]. The main benefits it offers are simplicity, minimal procedural time, decreased discomfort, low cost, quick rehabilitation, and decreased anaesthesia risks. These attributes render Pipelle sampling especially appealing in a busy and limited resource healthcare environment [13]. Although these benefits exist there are some concerns about quantity and quality of tissues retrieved by Pipelle. Lack of good specimens can be a problem in women who have cervical stenosis, an atrophic or thin endometrium, uterine cavity distortion, postmenopause, or technically challenging procedures [14]. In addition, since Pipelle is a limited sampling of the endometrial cavity, it may not be as sensitive in the case of focal endometriosis, like endometrial polyps [15].

Objective

To compare the adequacy of endometrial samples obtained through Pipelle sampling and conventional dilatation and curettage in women presenting with abnormal uterine bleeding.

This prospective comparative study was conducted at the Department of Gynae and Obstetrics, Saidu Group of Teaching Hospital, Swat, from from 1st Jan 2025 to 30th June 2025 and included 120 women presenting with abnormal uterine bleeding. All of the participants had their pipelle samples and all of their D&C samples analysed separately by a histopathologist. Women, 35-65 years old, with women presenting with abnormal uterine bleeding, such as heavy menstrual bleeding, irregular, intermenstrual, or post-menstrual bleeding were included. The participants included those with an indication for endometrial sampling, an endometrial thickness that needed further assessment by pelvic ultrasound and those who gave written informed consent for both procedures. Women who were pregnant or were suspected to be pregnant, women who had active pelvic inflammatory disease, women who had a recent genital tract infection, women who had a known bleeding disorder, women who had severe thrombocytopenia, women who had a cervical stenosis that precluded instrumentation, women who had a congenital uterine anomaly, women who had had a previous diagnosis of an endometrial malignancy, or women who were currently taking an anticoagulant were excluded. Women who had a clear diagnosis of a cervical malignancy, significant medical morbidity or who did not have a full histopathology report were also excluded. Data Collection After approval from the Institutional Ethical Review Committee, the eligible participants were selected by non-probability consecutive sampling. Each woman was informed about the purpose of the study, the procedure for the study, what she might experience as discomfort, and what might go wrong before giving written informed consent. Demographic data, as well as parity, menopausal status, duration and history of abnormal uterine bleeding, medical comorbidities, use of contraceptives and hormonal medications, and prior endometrial procedures, were obtained from patients. In addition, the results of pelvic ultrasonography were documented, such as the endometrial thickness, uterus size, fibroids, polyps, and other abnormalities. Pipelle sampling was done first under sterile conditions. The patient was positioned in the lithotomy position, and a sterile speculum was placed in the vagina to view the cervix. The cervix was cleaned with an antiseptic solution, and the Pipelle device was gently inserted through the cervical canal into the uterine cavity without the use of any cervical dilatation. The internal piston was pulled out to create negative pressure, and several rotations with the device and backward and forward movements were done to get endometrial tissue. The sample collected was stored at once in a 10% formal container container, separately labelled. The conventional D&C was then conducted under proper anaesthesia and following the hospital protocol. The cervix was progressively opened, and the lumen of the endometrium was systematically scraped with a sharp curette. The tissue sample retrieved was placed in another, distinct, labelled formalin container. The two specimens were identified with coded identification numbers so that the histopathologist could not have been.Both specimens were given coded ID numbers so that the histopathologist could not have known the sampling technique. The samples were subject to examination for tissue quantity, preservation, presence of endometrial glands and stroma and suitability for histopathological diagnosis. The presence of adequate endometrial glands and stroma allowed definite histopathological diagnosis to be made, and the specimen was considered adequate. Inadequate was considered if only blood, mucus, cervical tissue, or inadequate endometrial fragments were seen in the specimen. The primary outcome was sample adequacy, which was achieved by Pipelle sampling versus conventional D&C and the secondary outcomes were histopathological diagnosis, procedural duration, Visual Analogue Scale (VAS) pain score, requirement for cervical dilatation, procedural complications, and agreement between the two sampling techniques results. Statistical Analysis SPSS version 26.0 was used for data analysis. Continuous variables were expressed as mean ± SD or median (interquartile range), as appropriate according to the distribution of the data. Categorical variables like menopausal status, bleeding pattern, specimen adequacy, histopathological diagnosis, and complications were expressed as frequencies and percentages. The sample adequacy rates of Pipelle sampling and conventional D&C were compared by the McNemar test since both procedures were done on the same subjects. Cohen's kappa coefficient was used to evaluate the agreement between both the histopathologic diagnoses. Where appropriate, procedural duration and pain scores were compared using a paired-samples t-test. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of Pipelle sampling were calculated with respect to the conventional D&C histopathology as the reference method. The p value < 0.05 was deemed to be statistically significant.

The study included 120 women with a mean age of 46.8 ± 8.7 years and a mean BMI of 27.4 ± 4.6 kg/m². The mean parity was 3.6 ± 1.8, while 76 (63.3%) women were premenopausal and 44 (36.7%) were postmenopausal. Heavy menstrual bleeding was the most common presentation, reported by 43 (35.8%) participants, followed by postmenopausal bleeding in 30 (25.0%), irregular bleeding in 29 (24.2%), and intermenstrual bleeding in 18 (15.0%). The mean symptom duration was 7.9 ± 4.2 months, and the mean endometrial thickness was 11.6 ± 4.8 mm.

Table 1. Baseline demographic and clinical characteristics of participants

Adequate endometrial samples were obtained in 111 (92.5%) women through Pipelle sampling and in 116 (96.7%) through conventional D&C. Inadequate samples occurred in 9 (7.5%) and 4 (3.3%) women, respectively. Paired analysis showed that 109 (90.8%) women had adequate samples with both methods, while the difference in adequacy rates was not statistically significant (p=0.180).

Table 2. Comparison of sample adequacy between Pipelle sampling and conventional D&C

Paired distribution of sample adequacy

McNemar test was applied. The difference in sample adequacy between the two procedures was not statistically significant.

Proliferative endometrium was the most frequent finding, identified in 40 (33.3%) Pipelle samples and 39 (32.5%) D&C samples. Secretory endometrium was found in 27 (22.5%) and 28 (23.3%), while hyperplasia without atypia was detected in 10 (8.3%) and 11 (9.2%), respectively. Endometrial malignancy was identified in 3 (2.5%) Pipelle samples and 4 (3.3%) D&C samples. Overall diagnostic agreement was 91.7%, with a Cohen’s kappa of 0.84, indicating strong agreement between the two methods (p<0.001).

Table 3. Comparison of histopathological findings obtained through Pipelle sampling and conventional D&C

Pipelle sampling was significantly faster than D&C, with a mean procedure duration of 4.8 ± 1.6 versus 18.7 ± 5.4 minutes (p<0.001). Mean pain scores were also lower with Pipelle, at 3.1 ± 1.4 compared with 5.8 ± 1.7 for D&C (p<0.001). Cervical dilatation and anaesthesia were required in all 120 (100.0%) D&C procedures but only in 8 (6.7%) and 0 (0.0%) Pipelle procedures, respectively. Overall complications were less frequent with Pipelle, occurring in 4 (3.3%) women compared with 11 (9.2%) after D&C (p=0.049).

Table 4. Comparison of procedural characteristics, patient discomfort, and complications

In the present study 120 women with abnormal uterine bleeding were randomly assigned to Pipelle endometrial sampling or conventional dilatation and curettage (D&C). The mean age was 46.8 ± 8.7 years, while the mean body mass index was 27.4 ± 4.6 kg/m². Heavy menstrual bleeding was the most common symptom, and most participants were premenopausal. These are typical characteristics of the population that present with AUB, making it increasingly relevant to women of middle age and the peri-menopause to rule out AUB due to hyperplasia and malignancy. The rate of obtaining adequate endometrial tissue was 111 (92.5%) participants with sampling using Pipelle and 116 (96.7%) conventional D&C. The difference between the adequacy rates of D&C and other manufacturers was not significant (p=0.180), but was slightly higher for D&C. This means that pipelle sampling is able to yield diagnostic-quality tissue in most women who have AUB. Similar previous studies have reported 94% and 95% adequacy with Pipelle and D&C respectively [15]; and others 97.6% and 100% respectively with no significant difference [16]. The paired analysis revealed that 109 (90.8%) of the participants had adequate samples from both procedures. Seven women had an inadequate Pipelle specimen sample even though they had an adequate D&C specimen. This difference could be attributed to cervical stenosis, thinning of the endometrium, focal disease, or small amounts of endometrial tissue being removed using a narrow suction device. Insufficient endometrial samples has also been documented in women with atrophic and thin endometrium and that sampling failure is a significant limitation of office biopsy methods [18]. The most common histopathological findings were proliferative endometrium with 40 (33.3%) Pipelle and 39 (32.5%) D&C specimens, followed by secretory endometrium with 27 (22.5%) Pipelle and 28 (23.3%) D&C specimens. Hyperplasia without atypia was seen in 10 (8.3%) Pipelle samples and 11 (9.2%) D&C samples and malignancy in 3 (2.5%) and 4 (3.3%) respectively. These results show that the two methods are very similar in the case of diffuse endometrial abnormalities. Previous studies have also demonstrated their accuracy at detecting endometrial carcinoma and clinically significant endometrial pathology, both with Pipelle and conventional D&C [19]. The overall diagnostic agreement between Pipelle and D&C was 91.7% and the Cohen's Kappa coefficient was 0.84 (p<0.001), which is considered a strong agreement. This helps to keep the diagnosis reliability of Pipelle sampling in women who are selected for it. Similar rates of agreement were also reported in previous studies, as there was 97.6% agreement and a Kappa of 0.948 between the two methods. Less endometrial polyps were found with Pipelle than with D&C, however, 6 (5.0%) endometrial polyps were found by Pipelle as compared to 9 (7.5%) with D&C. This is a significant difference and is important for clinical use as there is a possibility of sampling only a portion of the uterine cavity with Pipelle and therefore missing focal lesions. Similarly, previous studies have shown lower sensitivity of blind sampling of the endometrium for focal lesions like polyps, and D&C or biopsy under hysteroscopic guidance may be more sensitive for identifying focal lesions. The mean duration of the procedure was significantly shorter with pipelle than with conventional D&C (4.8 ± 1.6 minutes vs. 18.7 ± 5.4 minutes, p<0.001). Previous studies also demonstrated significantly shorter procedures for Pipelle (mean of ~3.65 minutes) versus D&C (mean of 12.07 minutes). The advantage of this is that it is shorter, which is especially beneficial where operating theatres are scarce in busy outpatient departments and hospitals [20]. Patient discomfort was also greatly reduced using Pipelle sampling. The mean pain score was 3.1 ± 1.4 with Pipelle compared with 5.8 ± 1.7 following D&C (p<0.001). A similar difference was also previously reported, with the mean pain score of 1.64 for Pipelle and 5.81 for conventional D&C. The decreased pain could be due to the use of avoidance of routine cervical dilatation, uterine curettage and general anaesthesia. In the 8 (6.7%) Pipelle procedures, dilation of the cervix was necessary, whereas in all 120 (100.0%) D&C procedures, it was necessary. In addition, pipelle did not need any anaesthetic while all the conventional D&C procedures required anaesthetic. These results offer real-life potential benefits of Pipelle. Indeed, previous studies have cited Pipelle sampling as a speedy and economical technique which does not typically require the use of cervical dilatation or anaesthesia. A statistically significant difference was found with procedure-related complications, with 4 (3.3%) of the participants experiencing complications after Pipelle sampling and 11 (9.2%) after D&C. A previous study of Pipelle sampling also compared to conventional curettage for morbidity, mobility and return to daily activity and found it to be earlier, with fewer cases of morbidity [21].

Pipelle endometrial sampling provided a high sample adequacy rate that was statistically comparable to conventional D&C, with strong agreement between the histopathological findings of both methods. Pipelle was significantly faster, less painful, required minimal cervical dilatation, avoided anaesthesia, and was associated with fewer procedure-related complications. These findings support Pipelle sampling as an effective first-line outpatient method for endometrial evaluation in appropriately selected women with abnormal uterine bleeding. However, conventional D&C or hysteroscopy-guided biopsy remains necessary when the Pipelle sample is inadequate, focal pathology is suspected, or symptoms persist despite a benign result.

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