A new study, published in the Canadian Medical Association Journal, looked at the correlation between pregnancy and risk of traffic accidents. Pregnancy causes diverse physiologic and lifestyle changes that may contribute to increased driving error. Compared to a baseline risk for traffic accidents when not pregnant, there is a substantial increase in risk by the second trimester of pregnancy.

The study tracked 507,262 adult women that gave birth in Ontario, Canada from 2006 to 2011. They identified 6,922 motor vehicle crashes that these women accounted for over a three-year baseline period and 757 crashes during their second trimester. On average per month, that is 177 not pregnant and 252 while pregnant, a significant increase in risk.

The increased risk extended to diverse populations, varied obstetrical cases, and different crash characteristics. During the early second trimester, the increase in risk was most substantial, but it was compensated for by a drop in the third trimester. No similar increase was observed in crashes involving these women as passengers or pedestrians, cases of intentional injury, inadvertent falls, or other self-reported risky behaviors.

According to Reuters, symptoms associated with pregnancy are likely to result in distracted driving. A normal pregnancy is usually accompanied by a lot of fatigue, nausea, mood fluctuations, anxieties, and distractions, which may explain the increased risk of an accident.

The lead researcher, an internist at a Toronto hospital, developed the study after observing that pregnant women did not seem to consider the risk of driving. He was often asked about the risk associated with other activities, such as riding a rollercoaster, but never once asked about the risk of driving while pregnant. With the evidence presented by this study, the authors recommend doctors take time to emphasize road safety with their pregnant patients.