The objective of this study was to elucidate the normal functional adaptations of the cervix in pregnancy. Utilizing a Long-Evans rodent model, the cervix was divided into distal and proximal portions for virgin, mid-pregnant, and four weeks postpartum animals. The quasi-linear viscoelastic theory describes the elastic and viscous behavior of the cervix. A hydroxyproline assay was used to measure collagen content. The nonlinearity of the elastic response significantly increased throughout the entire cervix during pregnancy when compared to virgin samples (p < 0.05) and was similar to virgin samples postpartum. All viscous behavior, except for the short-term relaxation of the proximal cervix, significantly differed for pregnant specimens (p < 0.05) and remained similar to pregnant samples postpartum. Collagen content was found to increase by mid-pregnancy only in the proximal cervix when compared to virgin. Distal and proximal portions, however, were found to differ in collagen content at all time points (p < 0.05). This study finds that the cervix becomes elastically stiffer with increasing strain and exhibits increased viscous behavior during pregnancy, with incomplete recovery postpartum. These alterations allow for quick dissipation of loads, and are likely related to altered matrix organization and porosity reported by others.

中文翻译：

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妊娠和产后恢复对大鼠宫颈粘弹性行为的影响

本研究的目的是阐明妊娠期子宫颈的正常功能适应。利用 Long-Evans 啮齿动物模型，将宫颈分为处女、怀孕中期和产后 4 周动物的远端和近端部分。准线性粘弹性理论描述了子宫颈的弹性和粘性行为。羟脯氨酸测定用于测量胶原蛋白含量。与原始样品相比，怀孕期间整个子宫颈的弹性反应的非线性显着增加（p < 0.05），并且与产后原始样品相似。除了近端宫颈的短期松弛外，所有粘性行为对于怀孕样本都有显着差异（p < 0.05），并且与产后怀孕样本保持相似。与处女相比，仅在近端子宫颈中发现胶原蛋白含量在妊娠中期增加。然而，发现远端和近端部分在所有时间点的胶原蛋白含量不同（p < 0.05）。这项研究发现，随着压力的增加，子宫颈的弹性变硬，并且在怀孕期间表现出增加的粘性行为，产后恢复不完全。这些改变允许负载的快速消散，并且可能与其他人报告的改变的基质组织和孔隙率有关。这项研究发现，随着压力的增加，子宫颈的弹性变硬，并且在怀孕期间表现出增加的粘性行为，产后恢复不完全。这些改变允许负载的快速消散，并且可能与其他人报告的改变的基质组织和孔隙率有关。这项研究发现，随着压力的增加，子宫颈的弹性变硬，并且在怀孕期间表现出增加的粘性行为，产后恢复不完全。这些改变允许负载的快速消散，并且可能与其他人报告的改变的基质组织和孔隙率有关。