In a new study published in the Canadian Medical Association Journal researchers report that about one in 50 pregnant women will be involved in a serious motor-vehicle accident, typically during their second trimester.
Donald Redelmeier, MD, a physician in the University of Toronto Department of Medicine and a researcher at the Institute for Clinical Evaluation Sciences (ICES), is the study's lead author. He says that pregnant women frequently ask him about the safety of activities like air travel, scuba diving, and hot tubs, but most of them overlook traffic crashes, which are a greater threat during pregnancy.
For this study, researchers examined more than 500,000 Ontario women before, both during and after their pregnancies, following them for fpur years before delivery and one year after. The researchers examined whether typical pregnancy conditions such as nausea, fatigue, insomnia, and distraction were contributing to driver error and an increased risk of being involved in a traffic accident that required a hospital visit.
The study established a baseline in the period before pregnancy, when participants were involved in 6,922 crashes, an overall average of 177 per month. In contrast, women who were driving during their second trimester were involved in 252 crashes per month, which is a 42 percent increase over the baseline. Researchers found no similar increases for accidents in which the women were passengers or pedestrians, nor did they find an increase in the number of falls or risky behavior.
The reason for the link is not completely clear, but Dr. Redelmeier speculates that during the second trimester women may develop a false sense of security often compounded by insomnia, back pain, and a generally more hectic life.
"Once they've made it through the first trimester, their minds are more occupied with the birth of the child," he says. "They are often rushing to get things ready before the big day, so it's easier to be distracted."
Dr. Redelmeier adds that the study findings emphasize the need for pregnant women to consider safe driving as another element of good prenatal care, and reminds them to always wear a seatbelt, use turn signals, reduce speed, and minimize distractions. "It's a time to be extra vigilant."