How common are pelvic venous disorders in patients with unexplained chronic pelvic pain: a prospective cross-sectional study

This study is planned as an observational prospective cross-sectional study. A total of 490 women presenting with chronic pelvic pain (CPP) were screened. All participants underwent a standardized gynecological examination to exclude inflammatory, neoplastic, or endometriotic causes of pain. Following the application of predefined eligibility criteria, 83 patients with isolated CPP were enrolled as shown in Fig.  1 . Proportion estimates in this study refer specifically to the proportion of women with venous congestion among all women presenting with chronic pelvic pain during the study period, whereas detailed comparative analyses were performed within the final cohort of women with isolated CPP. The power analysis was conducted to estimate the ideal sample size; however, the final analyses were performed based on the available cohort, and the results should be interpreted accordingly. Fig. 1 Flowchart of patient selection. n: number, PID: pelvic inflammatory disease Flowchart of patient selection. n: number, PID: pelvic inflammatory disease The diagram above shows the patients included in the cohort. A total of 490 women presented to our clinic with chronic pelvic pain during the study period. Patients who declined to participate, had insufficient medical history, or refused clinical examination were excluded. After applying the predefined eligibility criteria, 83 women were included in the final cohort. These patients were then divided into two groups based on ovarian vein diameter for descriptive and comparative purposes. Those with a vein diameter < 6 mm were assigned to CPP without venous congestion (VC), and those with a diameter ≥ 6 mm were categorized as the CPP with venous congestion. At the initial visit, all participants underwent a structured clinical history and physical examination. Symptoms suggestive of non-gynecologic causes of pelvic pain (gastrointestinal, urological, and musculoskeletal) were specifically inquired and documented. However, systematic diagnostic investigations for non-gynecologic etiologies were not performed as part of the study protocol unless clinically indicated; therefore, the cohort was defined as ‘isolated CPP’ based on exclusion of identifiable gynecologic causes after standardized gynecologic evaluation. Women aged 18–60 years presenting with non-cyclic CPP of at least six months’ duration were considered for inclusion. Patients were excluded if identifiable gynecological conditions explaining pelvic pain were detected (e.g., endometriosis, leiomyomas, ovarian pathology, adenomyosis). Cases with no identifiable gynecologic cause for chronic pelvic pain after standardized gynecological evaluation were classified as isolated CPP and included in the final analysis. Participants were stratified according to ovarian vein diameter (≥ 6 mm vs. < 6 mm), a commonly used threshold reported in previous studies [ 12 ], and used in this study as a pragmatic grouping variable for comparative analysis rather than as a definitive diagnostic criterion for pelvic venous disorders. Demographic and clinical variables were systematically recorded, including age, gravidity, parity, mode of delivery (vaginal or cesarean), body mass index (BMI), menopausal status, use of oral contraceptives, presence of an intrauterine device (IUD), smoking and alcohol use, presence of systemic comorbidities, localization of pelvic pain, and history of antidepressant use within the preceding year. Transvaginal ultrasonography with Doppler was used as the primary imaging modality for the assessment of pelvic venous findings. Additional imaging methods such as CT, MRI, or catheter-directed venography were not routinely performed, as the study was designed as an epidemiological and exploratory evaluation reflecting routine gynecologic clinical practice. In daily practice, transvaginal ultrasonography represents the first-line imaging technique for the initial assessment of women with chronic pelvic pain. All participants underwent a standardized ultrasonographic examination performed by a single experienced clinician using an Arietta 65 ultrasound system (Hitachi, Tokyo, Japan), equipped with a 10–2 MHz transvaginal probe and a 3.5–5.0 MHz transabdominal convex probe. All examinations were performed in the supine position under aseptic conditions. The sonographic parameters shown in Table  1 were evaluated. Table 1 Sonographic parameters evaluated in the assessment of venous congestion Sonographic Parameter Definition/Criterion Tortuous tubular veins Presence of coiled veins adjacent to uterus Venous flow velocity Low velocity flow defined as < 3 cm/s Arcuate myometrial veins Visualization of arcuate veins within myometrium Retrograde venous flow Reversed blood flow detected on Doppler Polycystic ovarian morphology ≥ 12 follicles (2–9 mm) and/or ovarian volume > 10 mL Sonographic parameters evaluated in the assessment of venous congestion In this study, patients were classified according to ovarian vein diameter (≥ 6 mm vs. < 6 mm) as a pragmatic stratification variable to compare venous congestion–related sonographic features within a clinically homogeneous cohort. The images above illustrate representative examples of the ultrasonographic measurements performed in our study cohort. The images presented were obtained using transvaginal ultrasonography (TV-US) and Doppler ultrasonography (USG) during the study phase and belong to patients diagnosed with chronic pelvic pain (CPP). In a patient with PeVD, the diameter of the left ovarian vein was measured at 6.2 mm (A), and the ovarian venous flow velocity was observed to be 2.4 cm/s, with alterations in flow velocity noted during the Valsalva maneuver (B). Prominent venous structures adjacent to the uterus (C) and the presence of arcuate veins extending into the myometrium (D), along with venous tortuosity, are clearly visible. The diameter of the tortuous tubular vein was measured as 5 mm (E). In contrast, the left ovarian venous flow velocity in a CPP patient without venous congestion was measured at 3.9 cm/s (F) as shown in Fig.  2 . Fig. 2 TV-USG Images of patients monitored due to isolated PeVD TV-USG Images of patients monitored due to isolated PeVD Before initiating the study, a priori power analysis was conducted using G*Power version 3.1.9.7 (Heinrich-Heine University, Düsseldorf, Germany) to determine the minimum required sample size for comparing two independent groups. Based on the findings of Birch and Foran (2008), who reported moderate differences in mean pelvic pain scores among women with different etiologies of chronic pelvic pain, an effect size of d = 0.40 was assumed. Using a two-tailed independent-samples t-test with a significance level (α) of 0.05 and a desired statistical power (1 − β) of 0.80, the required total sample size was calculated as approximately 200 participants (100 per group). Statistical analysis was performed using IBM SPSS Statistics for MacOS, version 20.0. The distribution of continuous variables was assessed with the Shapiro-Wilk test. Normally distributed data were expressed as mean ± standard deviation and compared using Student’s t-test. Categorical variables were expressed as frequencies and percentages, and analyzed using the chi-square test. A p-value < 0.05 was considered statistically significant. Logistic regression and receiver operating characteristic (ROC) analyses were also employed to assess the diagnostic value of specific ultrasonographic parameters.

During the study period, a total of 490 women presented to our clinic with complaints of chronic pelvic pain (CPP). The patient selection process is shown in Fig.  1 . Of these, 107 patients were excluded due to incomplete clinical data, refusal to participate, or the presence of identifiable gynecologic causes. After applying the predefined eligibility criteria, 83 women were included in the final analysis. Of the 490 women presenting with chronic pelvic pain during the study period, venous congestion consistent with pelvic venous disorders was identified in 45 patients, corresponding to a proportion of 11.7% of all CPP presentations. Among the final cohort of 83 women, 45 were classified in the venous congestion group and 38 in the non-congestion group. When restricted to the final analytical cohort of 83 women with isolated chronic pelvic pain, venous congestion was observed in 54.2% of patients. The mean age was 37.78 ± 9.32 years, with an average gravidity of 3.11 ± 1.63 and parity of 2.59 ± 1.20. In the cohort, 45.78% of patients had a history of vaginal delivery and 37.34% had a history of cesarean section. Additional demographic and clinical characteristics are summarized in Table  2 . Table 2 Demographic characteristics of the Isolated CPP patient Group n 83 Age 37.78 ± 9.32 Gravida 3.11 ± 1.63 Parity 2.59 ± 1.20 Abortus 0.52 ± 0.83 BMI (kg/m²) 26.44 ± 3.94 Vaginal delivery n (%) 38 (45.78%) Cesarean delivery n (%) 31 (37.34%) Smoking n (%) 15 (18.07%) Alcohol use n (%) 2 (2.40%) OCP use n (%) 3 (3.61%) Menopause n (%) 12 (14.45%) Comorbid disease n (%) 16 (19.27%) Presence of IUD n (%) 21 (25.30%) Right lower quadrant pain n (%) 16 (19.27%) Left lower quadrant pain n (%) 28 (33.73%) Bilateral lower quadrant pain n (%) 39 (46.98%) Antidepressant use in the last year n (%) 33 (39.75%) Continuous variables are expressed as mean ± standard deviation, and nominal variables as n (%) n number, OCP Oral contraceptive pill, IUD Intrauterine device, BMI Body mass index Demographic characteristics of the Isolated CPP patient Group Continuous variables are expressed as mean ± standard deviation, and nominal variables as n (%) n number, OCP Oral contraceptive pill, IUD Intrauterine device, BMI Body mass index The table above presents the demographic characteristics of patients with isolated CPP. The table above presents a comparison of the demographic characteristics between the two groups. Patients were divided into two groups based on ovarian vein diameter: those without venous congestion (VC−, < 6 mm; n  = 38) and those with venous congestion (VC+, ≥ 6 mm; n  = 45). Comparison of demographic variables, including age, BMI, gravidity, parity, abortion rate, smoking and alcohol use, oral contraceptive use, menopausal status, presence of comorbidities, IUD use, and pain localization, revealed no statistically significant differences between groups ( p  > 0.05). However, antidepressant use within the past year was significantly higher in the VC+ group compared to the VC− group (53.33% vs. 23.68%, p  = 0.006) as shown in Table  3 . Table 3 Comparison of demographic characteristics between CPP without VC and CPP with VC groups Age CPP Without VC ( n  = 38) CPP With VC ( n  = 45) p -value* 39.78 ± 10.49 36.08 ± 7.92 0.086 Gravida 3.05 ± 1.72 3.15 ± 1.56 0.751 Parity 2.52 ± 1.26 2.64 ± 1.15 0.869 Abortus 0.52 ± 0.89 0.51 ± 0.78 0.550 BMI (kg/m²) 27.20 ± 3.93 25.79 ± 3.86 0.636 Vaginal delivery n (%) 22 (57.89%) 16 (35.55%) 0.418 Cesarean delivery n (%) 16 (42.10%) 15 (33.33%) 0.551 Smoking n (%) 10 (26.31%) 5 (11.11%) 0.073 Alcohol use n (%) 1 (2.63%) 1 (2.22%) 0.904 OCP use n (%) 3 (7.89%) 0 (0.00%) 0.055 Menopause n (%) 8 (21.05%) 4 (8.88%) 0.116 Comorbid disease n (%) 9 (23.68%) 7 (15.55%) 0.350 Presence of IUD n (%) 13 (34.21%) 8 (17.77%) 0.086 Right lower quadrant pain n (%) 11 (28.94%) 5 (11.11%) 0.401 Left lower quadrant pain n (%) 12 (31.57%) 16 (35.55%) 0.702 Bilateral lower quadrant pain n (%) 15 (39.47%) 24 (53.33%) 0.298 Antidepressant use in the last year n (%) 9 (23.68%) 24 (53.33%) 0.006** Significance levels between groups were calculated using T-test and Chi-square test n number, OCP Oral contraceptive pill, IUD Intrauterine device, VC Venous congestion, BMI: body mass index *Continuous variables are expressed as mean ± standard deviation, and nominal variables as n (%) **Statistically significant difference Comparison of demographic characteristics between CPP without VC and CPP with VC groups Significance levels between groups were calculated using T-test and Chi-square test n number, OCP Oral contraceptive pill, IUD Intrauterine device, VC Venous congestion, BMI: body mass index *Continuous variables are expressed as mean ± standard deviation, and nominal variables as n (%) **Statistically significant difference The table above summarizes the comparative ultrasonographic parameters between the two groups. Ultrasonographic evaluation demonstrated a significant difference in several parameters between groups. Tortuous tubular veins were observed in all patients within the ovarian vein dilatation group, although they were also present in a subset of patients without ovarian vein dilatation. (100%, p  < 0.001). Similarly, the mean diameter of tortuous tubular veins was significantly greater in the VC+ group (5.60 ± 0.67 mm vs. 3.76 ± 0.89 mm; p  = 0.041). Additional ultrasonographic features—such as low-velocity ovarian venous flow (< 3 cm/s), arcuate myometrial veins, and retrograde flow—were more common in the VC+ group, with low-velocity flow and arcuate veins showing statistically significant differences (both p  < 0.001). No significant differences were observed between groups in the presence of polycystic ovarian changes or lower extremity/vulvar varices as shown in Table  4 . Table 4 Comparison of Ultrasonographic Features Between CPP Without VC and CPP With VC Groups Presence of tortuous veins n (%) CPP Without VC ( n  = 38) CPP With VC ( n  = 45) p -value* 13 (34.21%) 45 (100%) < 0.001** Tortuous vein diameter (mm) 3.76 ± 0.89 5.60 ± 0.67 0.041** Presence of low velocity flow in ovarian vein (SOVF) n (%) 9 (23.68%) 30 (66.67%) < 0.001** Presence of arcuate myometrial veins n (%) 16 (42.10%) 39 (86.67%) < 0.001** Retrograde venous flow n (%) 8 (21.05%) 16 (35.55%) 0.147 Polycystic ovarian changes n (%) 4 (10.52%) 4 (8.88%) 0.801 Varices in vagina and/or lower extremity n (%) 18 (47.36%) 20 (44.44%) 0.790 n number, CPP Chronic pelvic pain, SOVF Low velocity flow in ovarian vein, VC Venous congestion *Continuous variables are expressed as mean ± standard deviation, and nominal variables as n (%) **Statistically significant difference Comparison of Ultrasonographic Features Between CPP Without VC and CPP With VC Groups n number, CPP Chronic pelvic pain, SOVF Low velocity flow in ovarian vein, VC Venous congestion *Continuous variables are expressed as mean ± standard deviation, and nominal variables as n (%) **Statistically significant difference Receiver Operating Characteristic Curve (ROC) analysis was performed to evaluate the diagnostic performance of key ultrasonographic findings in distinguishing VC+ from VC− groups as shown in Fig.  3 . Fig. 3 ROC Curves for ultrasonographic parameters associated with venous congestion in women with chronic pelvic pain. Red line: Arcuate Veins in the Myometrium. Blue line: Tortuous Tubular Veins. Green line: Slow Flow ROC Curves for ultrasonographic parameters associated with venous congestion in women with chronic pelvic pain. Red line: Arcuate Veins in the Myometrium. Blue line: Tortuous Tubular Veins. Green line: Slow Flow The area under the curve (AUC) was highest for the presence of tortuous tubular veins (AUC = 0.829), followed by arcuate myometrial veins (AUC = 0.723) and low velocity venous flow (AUC = 0.715). The AUC value obtained for tortuous tubular veins was above 0.8, suggesting good diagnostic accuracy of this parameter. In contrast, the AUC values for low flow velocity (0.715) and arcuate myometrial veins (0.723) indicated a moderate level of discriminative power. Regarding statistical significance, the p-value for tortuous tubular veins was 0.050, which was at the threshold of statistical significance, while p -values for low flow velocity and arcuate myometrial veins were 0.058, slightly above the conventional significance level as shown in Table  5 . This suggests that tortuous tubular veins may serve as a more reliable marker in this cohort, although these findings should be interpreted in light of the limited sample size. Additionally, the 95% confidence intervals (CIs) were 0.731–0.926 for tortuous tubular veins, 0.602–0.828 for low flow velocity, and 0.609–0.837 for arcuate myometrial veins. The higher lower bound of the CI for tortuous tubular veins (0.731), compared with those for low flow velocity (0.602) and arcuate veins (0.609), further supports its stronger diagnostic capacity. Table 5 ROC analysis for presence of tortuous veins, low velocity flow, and arcuate veins in myometrium Parameter AUC p 95% CI - Lower Bound 95% CI - Upper Bound Tortuous Veins 0.829 0.050 0.731 0.926 Low velocity Flow 0.715 0.058 0.602 0.828 Arcuate Veins in Myometrium 0.723 0.058 0.609 0.837 AUC Area Under the Curve ROC analysis for presence of tortuous veins, low velocity flow, and arcuate veins in myometrium AUC Area Under the Curve ROC analysis demonstrated moderate to good discriminative performance of selected ultrasonographic parameters. However, p-values were at or above the threshold of statistical significance for several variables. Therefore, these findings should be interpreted cautiously and considered exploratory and hypothesis-generating, particularly in light of the limited sample size.

Chronic pelvic pain (CPP) is defined as non-cyclic pain localized to the pelvic region, persisting for at least six months, and not exclusively associated with menstruation, pregnancy, or sexual activity. It affects approximately 12–15% of women of reproductive age and ranks among the most common reasons for gynecological consultations worldwide [ 1 , 2 ]. Beyond its prevalence, CPP is associated with substantial psychological, social, and functional impairments, often resulting in diminished quality of life and increased healthcare utilization [ 3 ]. The International Association for the Study of Pain (IASP) characterizes CPP by four essential criteria: pain refractory to standard medical treatment, limitation of physical functioning, vegetative symptoms of depression, and the presence of pain-related social disruption [ 4 ]. Despite advancements in imaging and diagnostic methodologies, the underlying cause remains undetermined in up to 60% of cases [ 5 ]. This diagnostic uncertainty contributes to delayed treatment, chronic symptomatology, and patient dissatisfaction. CPP may arise from a wide spectrum of etiologies, including gastrointestinal, urological, musculoskeletal, neurological, and gynecological disorders. While well-recognized gynecologic causes such as endometriosis, pelvic inflammatory disease (PID), leiomyomas, and adenomyosis are commonly investigated, Pelvic venous disorders (PeVD) have emerged as an often-overlooked but clinically significant contributor to CPP [ 6 , 7 ]. PeVD is a chronic pain disorder caused by pelvic venous insufficiency, typically involving reflux in the ovarian or internal iliac veins. It predominantly affects multiparous, premenopausal women and is characterized by pelvic pain exacerbated by prolonged standing, menstruation, or sexual activity [ 8 ]. The pathophysiology is thought to involve valvular incompetence in the ovarian veins, leading to venous stasis, pelvic varicosities, and subsequent nociceptive stimulation of surrounding tissues [ 9 , 10 ]. Imaging modalities used in PeVD diagnosis include transvaginal ultrasonography (TV-US), magnetic resonance imaging (MRI), computed tomography (CT), and selective ovarian venography. While MRI and CT allow for non-invasive assessment and differential diagnosis, ultrasonography and venography remain the most frequently used techniques [ 11 ]. Park et al. emphasized the diagnostic utility of transvaginal ultrasound, citing its high accuracy. Nevertheless, selective ovarian venography continues to be the gold standard despite its invasive nature [ 12 ]. Literature-based ultrasound criteria for PeVD include dilated pelvic veins (≥ 6 mm), low velocity venous flow (< 3 cm/s), reversed caudal flow, dilated arcuate veins in the myometrium, bilateral varicose pelvic veins, and polycystic ovarian changes [ 13 ]. Despite being first described in the mid-20th century, PeVD continues to be underdiagnosed, often mistaken for other pelvic pathologies. This is partly due to the limitations of traditional imaging modalities and a general lack of awareness among clinicians [ 14 ]. However, recent advances in transvaginal and Doppler ultrasonography have enabled better visualization of pelvic venous structures, providing a non-invasive and accessible method to identify PeVD-specific features [ 15 , 16 ]. In the study by Garcia-Jimenez et al., ovarian vein dilatation was identified as the most reliable ultrasonographic parameter for predicting pelvic venous disorders, with limited incremental value from additional Doppler or venous plexus findings [ 17 ]. For this reason, ovarian vein dilatation was used as the primary ultrasonographic parameter for group stratification in our study. Although PeVD is increasingly recognized as a possible cause of CPP, epidemiological data on its proportion remain scarce. Variations in proportion and diagnostic criteria emphasize the importance of further investigation and standardization. The present study aims to determine the proportion of CPP patients with sonographic venous congestion patterns consistent with PeVD in women with CPP using ultrasonographic evaluation and to assess the diagnostic value of specific ultrasonographic imaging markers. Additionally, the study explores the demographic and clinical characteristics associated with PeVD to enhance clinician awareness and facilitate earlier, more accurate diagnosis. Improved recognition of PeVD in the context of CPP may lead to more targeted treatment strategies and better patient outcomes.

This study suggests that pelvic venous disorders (PeVD) may represent an underrecognized contributor to chronic pelvic pain in women. In this selected cohort of women with isolated chronic pelvic pain, a substantial proportion showed sonographic findings suggestive of venous congestion, with ultrasonographic markers—including ovarian vein dilatation, tortuous tubular veins, low velocity venous flow, and arcuate myometrial veins—demonstrating imaging features supportive of venous congestion patterns. The higher proportion of antidepressant use among women with PeVD also reflects the broader symptom burden associated with this condition and highlights the potential need for multidisciplinary evaluation. Although pelvic venous disorders are often underrecognized, the present findings indicate that their proportion among women with chronic pelvic pain is not negligible. Given that more than one in ten women with CPP showed sonographic venous congestion patterns, clinicians may consider PeVD in the differential diagnosis of unexplained pelvic pain. Transvaginal and Doppler ultrasonography may serve as a useful first-line tool for identifying features suggestive of venous congestion and for guiding further clinical assessment. Further prospective studies with larger cohorts are needed to validate these findings and to better define their clinical significance. Given the exploratory nature of this study and its methodological limitations, the findings should be interpreted with caution.

This study was conducted to evaluate the relationship between pelvic venous disorders (PeVD) and chronic pelvic pain (CPP), and to determine the proportion of CPP patients with sonographic venous congestion patterns consistent with PeVD among patients with CPP. Our findings indicate that PeVD may represent a potential contributor to CPP and may warrant consideration during clinical evaluation. These results align with previous literature supporting the role of PeVD in the pathophysiology of CPP [ 2 , 18 , 19 ]. CPP is a multifactorial condition that severely impacts the quality of life in women and limits their daily functioning [ 2 ]. However, studies have shown that a specific cause cannot be identified in 30–40% of CPP patients [ 18 ]. Globally, CPP affects approximately 15% of women and is frequently reported in gynecology outpatient clinics [ 18 ]. In a previous study, pelvic venous disorders (PeVD) was diagnosed in 5% of women with chronic pelvic pain (CPP) in the United Kingdom, 7% in France, and 7% in the United States [ 20 ]. In our study, the proportion of CPP patients with sonographic venous congestion patterns consistent with PeVD among patients with chronic pelvic pain was found to be 11.7%. The proportion of CPP patients with sonographic venous congestion patterns consistent with PeVD reported in this study should therefore be interpreted within the context of a selected tertiary-care population with unexplained chronic pelvic pain. In less selected or community-based CPP populations, the relative contribution of pelvic venous disorders may differ due to the inclusion of a broader range of gynecologic and non-gynecologic pain etiologies. Nevertheless, focusing on a clinically homogeneous subgroup allowed for a more detailed exploration of venous congestion–related imaging features in patients in whom conventional causes of pelvic pain had already been excluded. The burden of CPP extends beyond physical symptoms, often resulting in significant psychosocial challenges. Its chronic and treatment-resistant nature is associated with depression, anxiety, and a marked decrease in quality of life [ 21 ]. Moreover, in our study a significantly higher rate of antidepressant use was observed among PeVD patients compared to non-PeVD CPP patients, highlighting the psychosocial burden of PeVD and the necessity for a multidisciplinary treatment approach. This finding should be interpreted within the well-described bidirectional relationship between chronic pain and mood disorders: depressive symptoms may amplify pain perception, while persistent pelvic pain may also lead to depression and anxiety and subsequent antidepressant treatment. As medication use was recorded as a clinical variable, causality cannot be inferred. Pelvic venous disorders represent a heterogeneous clinical entity in which no single imaging parameter is sufficient for diagnosis in isolation. In this context, each ultrasonographic finding evaluated in the present study should be interpreted as a complementary component rather than a standalone diagnostic criterion. Ovarian vein dilatation was used as a pragmatic stratification variable in our analysis, as it represents the most consistently reported and reproducible ultrasonographic marker in the literature. However, venous diameter alone does not imply reflux or symptomatic disease, and its diagnostic value increases only when interpreted alongside haemodynamic and morphological features. Since patient groups were defined based on ovarian vein diameter, comparisons of other related sonographic parameters should be interpreted with caution. Tortuous tubular veins adjacent to the uterus reflect venous remodeling secondary to chronic venous hypertension and were found to have the highest discriminative performance in our cohort. Low-velocity venous flow may indicate impaired venous drainage, while the presence of arcuate myometrial veins likely represents redistribution of venous outflow pathways. These findings should therefore be viewed as markers of venous congestion patterns rather than definitive diagnostic indicators of PeVD. The observed differences in additional ultrasonographic features between groups should therefore be interpreted as associations with venous congestion phenotypes, rather than as confirmatory diagnostic criteria. This approach avoids circular reasoning and allows for an exploratory assessment of individual imaging findings. Ultrasonography remains a valuable first-line modality in the evaluation of PeVD. Although catheter-directed venography remains the gold standard for the definitive diagnosis of pelvic venous disorders, its invasive nature limits its applicability in large-scale epidemiological or screening studies. In this context, ultrasonography represents a pragmatic first-line modality that may help identify patients who warrant further confirmatory imaging and potential intervention. Although various ultrasonographic parameters have been described, Garcia-Jimenez et al. reported that ovarian vein diameter is the most reliable diagnostic feature [ 17 ]. Accordingly, in our study, the venous congestion group was defined based on increased ovarian vein diameter. Park et al. demonstrated that PeVD patients exhibit significantly larger ovarian and pelvic vein diameters, more frequent venous reflux, and a higher proportion of periuterine varicosities compared with controls, and suggested that duplex ultrasonography is a useful non-invasive screening tool for selecting chronic pelvic pain patients who may benefit from further evaluation or venous intervention [ 12 ]. Consistent with the literature, we also found that the presence of myometrial arcuate veins was significantly associated with PeVD. However, polycystic ovarian morphology and pelvic varicocele were not statistically significant predictors in our cohort. Among the ultrasound parameters examined, tortuous tubular veins demonstrated the highest discriminative ability for identifying chronic pelvic pain associated with venous congestion, as indicated by ROC analysis. Accordingly, the ROC analyses in the present study should be considered exploratory and hypothesis-generating rather than confirmatory. Accordingly, the present study did not aim to identify the proportion of asymptomatic ovarian vein dilatation, but rather to explore venous congestion patterns among women presenting with clinically significant chronic pelvic pain of unknown origin. Ultrasonographic findings were therefore interpreted as adjunctive features that may support clinical suspicion, rather than as independent diagnostic determinants. This study has several limitations that should be acknowledged. First, it was conducted at a single tertiary referral center, which may introduce selection bias, as patients presenting to tertiary care institutions often represent a subset of women with more complex or treatment-resistant chronic pelvic pain. In addition, the application of strict exclusion criteria to define isolated chronic pelvic pain resulted in the exclusion of a substantial proportion of real-world CPP etiologies, which may limit the generalizability of the reported prevalence estimates to unselected populations. Second, although an a priori power calculation suggested a larger sample size, the final cohort consisted of 83 patients. Recruitment goals could not be fully achieved due to strict inclusion criteria, patient refusal, and incomplete clinical data. Consequently, the study may be underpowered to detect smaller between-group differences, and nonsignificant findings—particularly for secondary outcomes—should be interpreted with caution. Third, the study did not include longitudinal follow-up or standardized treatment outcomes. As the primary aim was epidemiological and exploratory in nature, therapeutic interventions were not systematically recorded, precluding conclusions regarding treatment response or symptom evolution. Additionally, grouping patients according to ovarian vein diameter and subsequently comparing other related sonographic features between these groups may introduce a degree of circularity; therefore, these comparisons should be interpreted cautiously. Finally, although patients were classified as having isolated CPP based on standardized gynecologic evaluation, non-gynecologic etiologies such as musculoskeletal, gastrointestinal, or neuropathic causes could not be fully excluded. This approach reflects routine clinical practice, in which gynecologic assessment represents the first step in the evaluation of women with chronic pelvic pain.