Shorter pregnant women restrained in the rear seat of a car are at risk for serious neck injuries: Biomechanical analysis using a pregnant crash test dummy.

Introduction: When considering seat belt contacts to the neck in pregnant woman of shorter height sitting in the rear seat of a vehicle, subsequent injuries after a collision must be understood in the context of both maternal and fetal outcomes. To determine likely injuries to a pregnant woman sitting in the rear seat, we determined the kinematics of a "pregnant" crash test dummy by measuring neck compression forces and biomechanical parameters acting on the head and neck.

Methods: Sled tests using a shorter-height pregnant woman crash test dummy (Maternal Anthropometric Measurement Apparatus, ver. 2B) were performed at the HYGE sled test facility representing full frontal impact at target velocities of 29km/h and 48km/h. Kinematics of the dummy and biomechanical parameters of the head, neck, and chest were measured. Pressure to the neck was measured using Prescale (Fujifilm, Tokyo, Japan).

Results: During frontal collision tests, the shoulder belt compressed the neck at a pressure >12.8MPa, even during the low-velocity impact. In addition to neck flexion, right side bending and the head and chest moving in opposite directions were observed, with maximum differences of 42.4mm at high velocity and 33.7mm at low velocity.

Conclusions: This study provides data on the kinematics of pregnant women of short height sitting in the rear seat during a frontal collision using a pregnant woman crash test dummy. The knowledge gathered from this study should be useful for determining pregnant women passengers' kinematics at the time of collision and evaluating the relationship between the vehicle collision and fetal outcomes.