According to Canadian researchers who studied records of more than 500,000 women for six years from 2006 to 2011, Women run a 42 % increased relative risk of being in a motor vehicle accident when they’re pregnant than when they’re not. The risk is especially acute during the first month of the second third of pregnancy. The risk was higher in the fall and winter, when the weather is worse, and in the afternoons, the study found. Car crashes are the leading cause of fetal death linked to trauma in mothers.