Dynamic tensile properties of human placenta

Area of Science:

• Biomechanics
• Maternal-fetal health
• Computational modeling

Background:

• Automobile crashes are a leading cause of injury death in pregnant females and traumatic fetal injury mortality.
• Current computational models for assessing fetal risk in crashes rely on limited quasi-static material data of the placenta.
• Dynamic material properties are crucial for accurate biomechanical simulations of pregnant occupants.

Purpose of the Study:

• To determine the dynamic material properties of the human placenta under uniaxial tensile loading.
• To provide data for enhancing computational models used in motor vehicle crash simulations involving pregnant occupants.
• To investigate the mechanical behavior of the maternal placental side and the chorion layer.

Main Methods:

• Conducted 20 dynamic uniaxial tensile tests on the maternal side of the placenta and 10 on the chorion layer.
• Utilized human placentas from 6 donors for testing.
• Determined material properties at a strain rate of 7.0 strains/s.

Main Results:

• Average peak strain at failure was similar for both the maternal portion (0.56) and the chorion layer (0.61).
• The chorion layer exhibited significantly higher average failure stress (167.8 kPa) compared to the placenta without the chorionic plate (18.6 kPa).
• Structural and functional differences between placental layers contribute to variations in mechanical strength.

Conclusions:

• Dynamic loading data for the placenta have been successfully determined.
• These data are essential for improving computational models of pregnant occupant kinematics in motor vehicle crashes.
• Computational models should incorporate the material properties of the placenta excluding the chorion layer for greater accuracy.