Do mechanical properties of human fetal membrane depend on strain rate?

Abstract

Aim: The objective of this study was to examine the effect of strain rate on the mechanical properties of human fetal membranes.

Methods: Different strain rates were employed to quantify the stress-strain relation of the chorioamnion membrane. The mechanical properties of nine human amnion membranes, four collected from cesarean delivery and five collected from normal vaginal delivery, were examined in uniaxial tension tests under strain rates of 0.1, 1 and 10%/min.

Results: Statistical analysis revealed significant (P < 0.05) correlation between the change in strain rate and the elastic modulus as well as failure strain of amnion samples. The rupture stress, though, did not show dependency on strain rates.

Conclusion: Human chorioamnion is strongly viscoelastic. By increasing the rate of the test, the stiffness of amnion increases considerably.

Keywords: chorioamnion (fetal membrane); rupture stress; strain rate; uniaxial tension test; viscoelastic.