Manoogian 1 PREGNANT OCCUPANT INJURY RISK USING COMPUTER SIMULATIONS WITH NCAP VEHICLE CRASH TEST DATA

Automobile crashes are the largest single cause of death for pregnant females and the leading cause of traumatic fetal injury mortality in the United States. A previously validated MADYMO computer model of a 30-week pregnant occupant was used in this study to investigate the pregnant occupant response in a New Car Assessment Program (NCAP) frontal barrier motor vehicle crash. The effect of the restraints, all tests had a 3 point seatbelt and an airbag, and the vehicle performance in the crash are incorporated by applying the measured pelvic acceleration in the front seat passenger dummy to the pregnant occupant model. Included in the study are nine vehicle models that represent the compact, medium, and sport utility vehicle classes during the years 1996 to 2006 for a total of 26 NCAP tests with corresponding simulations. Uterine strain from the computational model, a good predictive measure of the risk of fetal injury due to placental abruption, indicates the average risk of adverse fetal outcome associated with these NCAP tests is 85 ± 13% with a minimum risk of 55% and a maximum risk of 100%. NCAP star rating correlates with the risk of adverse fetal outcome (p=0.001) with 3 stars having an average risk of 99 ± 3% (n=3), 4 stars having an average risk of 89 ± 11% (n=14), and 5 stars having an average risk of 75 ± 13% (n=9). However, even the best NCAP rating, 5 stars, is still indicative of a high risk of fetal injury. This high risk is consistent with published pregnant occupant case studies that have an equivalent change in velocity of slightly more than 56.3 kph (35 mph). Although this study is limited to computational modeling, it suggests more research in protecting the pregnant occupant is needed.