The mechanical properties of prematurely and non--prematurely ruptured membranes. Methods and preliminary results.

The mechanical properties of the chorioamniotic membranes have been studied by several investigators over the past 100 years. No relationship between membrane strength, as measured by rupture tension, and premature or non-premature rupture of the membranes has been demonstrable. In the present study, several measures of the mechanical properties of the chorioamniotic membranes were examined. These included thickness, rupture tension, work to rupture, strain to rupture, and moduli of elasticity (Young). Prematurely and non-prematurely ruptured membranes differed with respect to thickness near the rupture site and Young's modulus near the placenta. Differences between the groups for the other parameters were not significant. This study suggests that there may be inherent differences between membranes which rupture prematurely and those which do not.