Menstrual Pain and Elasticity of Uterine Cervix

Abstract

Menstrual pain is consequent to intense uterine contraction aimed to expel menstrual flow through downstream uterine cervix. Herein it was evaluated whether characteristics of uterine cervix are associated with intensity of menstrual pain. Ultrasound elastography was used to analyze cervix elasticity of 75 consecutive outpatient women. Elasticity was related to intensity of menstrual pain defined by a Visual Analogue Scale (VAS). Four regions of interest (ROI) were considered: internal uterine orifice (IUO), anterior (ACC) and posterior cervical (PCC) compartment and middle cervical canal (MCC). Tissue elasticity, evaluated by color score (from 0.5 = blue/violet (low elasticity) to 3.0 = red (high elasticity), and percent tissue deformation was analyzed. Elasticity of IUO was lower (p = 0.0001) than that of MCC or ACC, and it was negatively related (R2 = 0.428; p = 0.0001) to menstrual VAS (CR −2.17; 95%CI −3.80, −0.54; p = 0.01). Presence of adenomyosis (CR 3.24; 95% CI 1.94, 4.54; p = 0.0001) and cervix tenderness at clinical examination (CR 2.74; 95% CI 1.29, 4.20; p = 0.0004), were also independently related to menstrual VAS. At post hoc analysis, women with vs. without menstrual pain had lower IUO elasticity, expressed as color score (0.72 ± 0.40 vs. 0.92 ± 0.42; p = 0.059), lower percent tissue deformation at IUO (0.09 ± 0.05 vs. 0.13 ± 0.08; p = 0.025), a higher prevalence of cervical tenderness at bimanual examination (36.2% vs. 9.5%; p = 0.022) and a higher prevalence of adenomyosis (46.5% vs. 19.9%; p = 0.04). These preliminary data indicate that IUO elasticity is associated with the presence and the intensity of menstrual pain. Mechanisms determining IUO elasticity are useful to be explored.

The Benefit of Transvaginal Elastography in Detecting Deep Endometriosis: A Feasibility Study

“…Accordingly, it is not feasible to appropriately define absolute stiffness by this method. Usually, the stiffness ratio of sites of interest and adjacent tissue is more appropriate to eliminate inter-operator variability, as the compression and decompression exerted by the operator similarly af-fect the two areas [10,25,26]. In this study, the stiffness ratio of two areas of the same tissue surrounding the nodule was compared with the stiffness of the nodule.…”

“…The strain value can be depicted using colored shading superimposed on the B-mode image. The strain of different regions of interest (ROI) can be concomitantly evaluated, and the strain ratio, a measure of the discrepancy in the elasticity of different tissues, can be used to improve SE accuracy [10,20,21]. For image acquisition in B-mode, the vaginal probe was positioned in the region of the endometriotic nodule.…”

“…Volume (cm3) of endometriotic nodules identified in B-mode was evaluated by the ellipsoid formula (3 main diameters × 0.5223). Tissue stiffness/elasticity was evaluated by SE, which measures tissue deformation or displacement provoked by an applied pressure [10,12,13]. The strain value can be depicted using colored shading superimposed on the B-mode image.…”

“…Several studies have now shown that transvaginal sonography (TVS) performed by an expert sonographer can be regarded as being an accurate method in defining DIE nodules and their extension, as magnetic resonance imaging (MRI) [5,8,9]; although, accurate diagnosis of nodules of the uterosacral ligaments and parametrium remains problematic [5]. Strain elastography (SE) measures tissue stiffness/elasticity and is commonly used to characterize lesions of the breast and other organs [10,11]. DIE lesions are stiffer than normal surrounding tissue, but few studies have applied SE to their characterization [12,13].…”

Angle of Uterine Flexion and Adenomyosis

“…During contraction, intra-lumen endometrial pressure increases up to 300 mmHg, and marked distortion of the intra-lumen profile can be observed [ 15 , 16 ]. A stiffer inner uterine orifice (IUO) is harder to dilate, and by counteracting menstrual blood expulsion, menstrual pain increases [ 17 ]. An increased angle of uterine flexion may also reinforce the “valve” sited at the IUO, causing stronger uterine contractions and a higher intensity of menstrual pain [ 9 ].…”