Way back in the 1990s, Donald Redelmeier noticed a trend in cell phone use and car crashes in his work as an emergency room (ER) doctor in Ontario. Curiosity led him to conduct one of the first studies identifying a link between cell phone use and automobile accidents.

Driving while pregnantLately, Redelmeier’s curiosity was aroused by car crashes involving pregnant drivers. Again, he turned to scientific research to see if his hunch was correct. It is. Redelmeier’s findings reveal a woman driver is 42% more likely to be involved in a car crash that sends her to the ER during the second trimester of pregnancy than she is before or after pregnancy.

Redelmeier describes the ER as “the last thing an expectant mom needs.” Fear and trauma are frightening enough and threats to the pregnancy can become very real in a car accident.

What many people may not realize, however, is the dilemma ER personnel must confront when a pregnant car crash patient is presented for treatment. The standard procedures for car crash patients - scans, x-rays, emergency drugs, and the like - cannot be used during pregnancy.

Redelmeier’s study was a review of motor vehicle accidents among women who had babies in Ontario between April 2006 and April 2011. Additional criteria included:

  • No women younger than 18
  • No one living outside Ontario
  • No one in the care of a midwife

The research revealed:

  • 507,262 women giving birth during the study period
  • 6,922 were drivers during crashes occurring in the three years before pregnancy (177 crashes per month)
  • 4.3/1,000 women were involved in a car crash before pregnancy
  • 575 crashes during the second trimester (252 crashes per month)
  • 7.7 of every 1,000 was in a crash during the second trimester

All car crashes involved women across the demographic spectrum and across the obstetrical spectrum. The crashes were caused by a variety of reasons (all avoidable, according to Redelmeier).

The study followed women three years before pregnancy, during pregnancy, and one year after delivery. During the first trimester, crash rates were about the same as before pregnancy. During the third trimester, the crash rate dropped back down to pre-pregnancy and early-pregnancy rates and remained at the low level for one year after childbirth.

The Redelmeier research team did not explore the reason why so many crashes occur during the second trimester but he suspects certain effects of pregnancy - “fatigue, insomnia, nausea, and stress” - make women more distracted behind the wheel during that time.

“The magnitude of the effect...It’s a substantial risk,” leads Redelmeier to suggest driving safety to be included in prenatal care programs. A life-threatening motor vehicle crash, he says, truly is the last thing an expectant mom needs.

Source: Redelmeier, Donald A., et al. “Pregnancy and the risk of a traffic crash.” CMAJ. Canadian Medical Association. May 12, 2014. Web. May 20, 2014.