Oyen Michelle L, Calvin Steven E, Landers Daniel V
Department of Biophysical Sciences and Medical Physics, University of Minnesota, Minneapolis, USA.
Am J Obstet Gynecol. 2006 Aug;195(2):510-5. doi: 10.1016/j.ajog.2006.02.010. Epub 2006 May 2.
The objective of the study was to evaluate the relative contributions of amnion and chorion to the strength of fetal membranes and to correlate these findings with gestational age.
Fetal membranes from 78 pregnancies were tested for biaxial puncture force using a blunt, instrumented probe with a low-force load cell connected through a load cell conditioner to an oscilloscope. The average of 2 to 4 tests performed on independent regions of the membrane was recorded. Means and SDs were calculated through the gestational age ranges of less than 32, 32 to 36, or 37 weeks or longer. Linear regression analysis was performed across gestational age after grouping data by labor and mode of delivery.
There were trends toward decreasing puncture force with gestational age for both chorioamnion and amnion for both vaginal deliveries and cesarean sections. The trends were significant by linear regression for labored deliveries but not unlabored cesarean sections for both chorioamnion and amnion alone. There was no trend in chorion puncture force with either gestational age or delivery mode and the mean puncture force values were, on average, half those for the amnion.
The amnion is significantly stronger than the chorion when subjected to biaxial strength testing. The amnion but not the chorion is significantly affected by the chemical and mechanical changes during gestation and the labor process. These data will help direct future studies on the effects of clinical and molecular modulators of inflammation on membrane rupture thresholds with special emphasis on the biochemical and structural changes in the amnion.
本研究的目的是评估羊膜和绒毛膜对胎膜强度的相对贡献，并将这些发现与孕周相关联。
使用钝头、带有仪器的探头对78例妊娠的胎膜进行双轴穿刺力测试，该探头带有低力称重传感器，通过称重传感器调节器连接到示波器。记录在胎膜独立区域进行的2至4次测试的平均值。计算小于32周、32至36周或37周及更长孕周范围内的平均值和标准差。在按分娩方式和分娩模式对数据进行分组后，对整个孕周进行线性回归分析。
对于阴道分娩和剖宫产，羊膜绒毛膜和羊膜的穿刺力均有随孕周增加而降低的趋势。对于有产程的分娩，通过线性回归分析，这些趋势具有显著性，但对于单独的羊膜绒毛膜和羊膜，未临产的剖宫产则无显著性。绒毛膜穿刺力在孕周或分娩方式方面均无趋势，平均穿刺力值平均为羊膜的一半。
在进行双轴强度测试时，羊膜明显比绒毛膜更强。羊膜而非绒毛膜在妊娠和产程中的化学和机械变化中受到显著影响。这些数据将有助于指导未来关于炎症的临床和分子调节剂对胎膜破裂阈值影响的研究，特别强调羊膜中的生化和结构变化。
