A recent study from U of T and Sunnybrook Hospital researchers published in the Canadian Medical Association Journal suggests that pregnant women who drive are at an increased risk of a serious crash during the second trimester of their pregnancy.

Motor vehicle crashes are among the leading causes of maternal trauma during pregnancy and can lead to fetal deaths or neurological deficits in surviving infants. “Every crash creates worry and potential future litigation that might have been avoided if the crash had been prevented,” the study says.

Dr. Donald Redelmeier of the U of T Department of Medicine is the principal investigator of the study. Along with three researchers, he conducted a population-based analysis of women who gave birth in Ontario hospitals between April 1, 2006 and March 31, 2011. The study excluded minors, women who were not Ontario residents, and those who lacked a valid health card.

The purpose of the study was to compare the risk of having a motor vehicle crash during the second trimester to the risk of a crash before pregnancy.

The study considers the records of a total of 507, 262 women as well as the corresponding emergency visits due to the crash for up to a five-year period for each subject, where the three years before the pregnancy served as the baseline.

The study defines a “serious crash” as a visit to the emergency room due to a collision but, beyond that classification, the severity of the collision was not considered.

The researchers found that the baseline (before pregnancy) accident rate was 4.55 accidents for every 1000 women, which is double the population average. However, this may be due to an increased number of young drivers in the study cohort.

The accident rate went up to a 6.47 during pregnancy — a whopping 42 per cent increase from the baseline. The highest risk of crashing was found to be during the early phase of the second trimester.

This increased risk was consistent among women from various age groups and socioeconomic backgrounds. It was also consistent between women who had a full-term pregnancy and those who did not.

This study raises an important social and public health concern. The authors conclude that the findings merit attention for prenatal care. Safety precautions such as avoiding speeding, minimizing distractions, and signaling turns were mentioned in the study.