Around 80% of women experience vaginal tears during labour when the diameter of the vagina must increase to allow the passage of a full-term baby. Current techniques for evaluating vaginal tears are qualitative and often lead to an incorrect diagnosis and inadequate treatment, severely compromising the quality of life of women. In order to characterize the failure properties of the vaginal tissue, whole vaginal tracts from rats (n = 18) were subjected to free-extension inflation tests until rupture using a custom-built experimental set-up. The resulting deformations were measured using the digital image correlation technique. Overall, the strain and changes in curvature in the hoop direction were significantly larger relative to the axial direction. At a failure pressure of 110 ± 23 kPa (mean ± s.d.), the hoop and axial stresses were computed to be 970 ± 340 kPa and 490 ± 170 kPa, respectively. Moreover, at such pressure, the hoop and axial strains were found to be 12.8 ± 4.4 % and 6.4 ± 3.7 % , respectively. Rupture of the vaginal specimens always occurred in the hoop direction by tearing along the axial direction. This knowledge about the rupture properties of the vaginal tissue will be crucial for the development of clinical approaches for preventing and mitigating vaginal tearing and the associated short- and long-term traumatic conditions.

中文翻译：

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阴道组织的膨胀和破裂。

当阴道直径必须增加以允许足月婴儿通过时，大约80％的妇女在分娩时会经历阴道撕裂。当前评估阴道泪液的技术是定性的，通常会导致错误的诊断和治疗不足，从而严重损害妇女的生活质量。为了表征阴道组织的衰竭特性，使用定制的实验装置对大鼠（n = 18）的整个阴道道进行自由伸展的充气测试，直到破裂。使用数字图像相关技术测量所得的变形。总体而言，沿圆周方向的应变和曲率变化相对于轴向方向明显更大。在110±23 kPa（平均±sd）的破坏压力下，计算得出的环向应力和轴向应力分别为970±340 kPa和490±170 kPa。此外，在这样的压力下，发现环向应变和轴向应变分别为12.8±4.4％和6.4±3.7％。阴道标本的破裂总是通过沿轴向撕裂而沿箍圈方向发生。对阴道组织破裂特性的了解对于开发预防和减轻阴道撕裂以及相关的短期和长期创伤状况的临床方法至关重要。