Proceedings of the 24th World International Traffic Medicine Association Congress, Qatar 2015
  • ISSN: 2223-0440
  • EISSN:


Pregnancy causes diverse physiologic and lifestyle changes that may contribute to increased driving and driver error. We compared a woman’s risk of a serious motor vehicle crash during her second trimester to her own baseline risk before pregnancy. We conducted a population-based self-matched exposure-crossover longitudinal cohort analysis of women who gave birth in Ontario, Canada, between April 1, 2006 and March 31, 2011 (5 years). We excluded women less than age 18 years, individuals living outside Ontario, those who lacked a valid identifier number under universal insurance, and cases managed by a midwife. The primary outcome was a motor vehicle crash resulting in a hospital emergency department visit. A total of 507,262 women gave birth during the study (mean age = 30 years, middle-low socioeconomic status = 64%, cesarean section rate = 30%). The women accounted for a total of 6,922 motor vehicle crashes as drivers during the three-year baseline interval (177 per month) and 757 motor vehicle crashes as drivers during their second trimester (252 per month). The elevated risk during the middle of pregnancy equaled a 42% increase in crash risk (95% confidence interval 32 to 53, p < 0.001). The increased risk included diverse populations, varied obstetrical cases, and different crash characteristics. The increased risk was largest in the early second trimester and compensated during the third trimester. No increase was observed in incidents involved as passengers or pedestrians, cases of intentional injury or inadvertent falls, or self-reported risky behaviors. The absolute risk amounted to an estimated 1-in-50 women experiencing a motor vehicle crash at some point during an average pregnancy, taking into account all nine months and the full spectrum of severity (fatal, injury, and vehicle damage combined). We suggest that pregnancy is associated with an increased risk of a serious motor vehicle crash during the second trimester that may merit attention in prenatal care guidelines.


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  • Article Type: Research Article
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