Pelvic pain and venous congestion revisited: examining relationship between chronic pelvic pain and uterine venous size and blood flow.

OBJECTIVE: To investigate the relationship between increased uterine venous plexus diameter and chronic pelvic pain in women attending a gynecology clinic. METHODS: This was a retrospective study of patients attending a tertiary university hospital in London, UK. Women presenting to the gynecology clinic undergoing transvaginal ultrasound examination were recruited into the study. The largest trunk of the uterine venous plexus was measured on each side. Blood flow within the uterine veins was categorized into continuous or interrupted flow and evaluated using color and spectral Doppler ultrasound during normal respiration and on Valsalva maneuver to demonstrate the presence of venous reflux. The largest uterine vein diameter and its blood flow were used for the analysis. The main variables of interest were chronic pelvic pain, uterine vein diameter and type of blood flow. RESULTS: We included 1500 women in the study, of whom 584 (38.9% (95% CI, 36.5-41.5%)) reported chronic pelvic pain. Dysmenorrhea was the most common type of pelvic pain. Age (P < 0.001), menopausal status (P = 0.02), varicose veins (P = 0.01), adenomyosis (P < 0.001) and endometriosis (P < 0.001) were found to be independently associated with the occurrence of pain on multiple logistic regression analysis. There was no difference in uterine vein diameter between women with and those without pain (P = 0.10). Neither uterine vein diameter (P = 0.47) nor type of blood flow (P = 0.07) was significantly associated with the occurrence of pelvic pain on multiple logistic regression. CONCLUSIONS: Our findings show that uterine vein diameter is not associated with pelvic pain. However, we found other important clinical and demographic factors that are associated with chronic pelvic pain. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

The effect of pelvic pathology on uterine vein diameters.

BACKGROUND: Transvaginal ultrasound (TVS) is a sensitive tool for detecting various conditions that contribute to pelvic pain. TVS can be also used to assess blood flow and measure the size of pelvic veins. Pelvic venous congestion (PVC) is characterised by enlargement of the pelvic veins and has been recognised as a cause of chronic pelvic pain. The reference ranges for uterine venous diameter in women with normal pelvic organs have been established, but there is no information regarding the potential effect of pelvic pathology on the uterine venous diameters. The aim of this study was to examine the size of uterine venous plexus in women with evidence of pelvic abnormalities on TVS and to determine whether the reference ranges need to be adjusted in the presence of pelvic pathology. A prospective, observational study was conducted in our gynaecological outpatient clinic. Morphological characteristics of all pelvic abnormalities detected on TVS and their sizes were recorded. The uterine veins were identified and their diameters were measured in all cases. The primary outcome measure was the uterine venous diameter. Regression analyses were performed to determine factors affecting the uterine venous size in women with pelvic pathology. RESULTS: A total of 1500 women were included into the study, 1014 (67%) of whom were diagnosed with pelvic abnormalities. Women with pelvic pathology had significantly larger uterine venous diameters than women with normal pelvic organs (p < 0.01). Multivariable analysis showed that pre-menopausal status, high parity, presence of fibroids (p < 0.001) and Black ethnicity were all associated with significantly larger uterine vein diameters. Based on these findings modified reference ranges for uterine venous diameters have been designed which could be used for the diagnosis of PVC in women with uterine fibroids. CONCLUSIONS: Our findings show that of all pelvic pathology detected on TVS, only fibroids are significantly associated with uterine venous enlargement. Factors known to be associated with enlarged veins in women with normal pelvic organs, namely parity and menopausal status, also apply in patients with pelvic pathology. Future studies of uterine venous circulation should take into account the presence and size of uterine fibroids when assessing women for the signs of PVC.