Researchers published their findings in the Canadian Medical Association Journal, according to the Los Angels Times. They combed through the medical histories of 500,000 women who gave birth between 2006 and 2011 to determine their crash rates before, during and after pregnancy. The average rate of car accidents reported in medical records for the group of women before pregnancy was 4.33 crashes per 1,000 women per year. In the first month of the second trimester that rate rose dramatically to 7.66 collisions per 1,000 women per year. The increased crash risk came regardless of age, socioeconomic status or any other factors.
All told, the numbers showed a 1 in 50 statistical risk of the average women having a motor vehicle crash at some point during her pregnancy.
Researchers speculated about what caused the increase in car crashes. They questioned whether fatigue, distraction, nausea or other annoyance that accompanies pregnancy might make a woman more vulnerable while behind the wheel.
The safest month turned out to be the last month of pregnancy. The researchers tracked only 2.74 crashes per 1,000 women. A year after giving birth their crash rates were half of what they were before pregnancy at 2.35 crashes per 1,000 women per year.