Abstract
Motor vehicle collisions (MVCs) are the most common etiology of trauma and non-obstetric fetal death among pregnant individuals. Seat belts prevent MVC-related injuries; however, some pregnant individuals do not wear a seat belt due to discomfort and concerns about belt-related safety for their fetus. Highlighted by stagnating seat belt use rates over time and potential for incorrect usage, seat belt effectiveness among pregnant occupants requires further study. Here, crash data 1998-2021 for pregnant occupants from National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) and the Crash Investigation Sampling System (CISS) were analyzed to: 1) evaluate the effectiveness of seat belts on preventing whole-body injury outcomes; 2) evaluate the effectiveness of seat belts on preventing body region-specific injuries; and 3) investigate vehicle- and occupant-specific factors that modify the risk of injuries. Adjusted for occupant and vehicle factors, seat belts prevented whole-body injuries as well as injuries to critical body regions such as the brain, thorax, and pelvis. Although three-point seat belts are effective in improving injury outcomes for pregnant occupants overall, there is room to improve their effectiveness for specific body regions (e.g., abdomen, uterus/placenta). Importantly, no elevated injury risk to pregnant occupants from wearing a seat belt during an MVC was found.