When you tell people you’re pregnant, the first thing you get is advice. It comes from friends, from relatives, from books, from your doctor, from random people on the street, from signs and warnings on various products. Do this. Don’t do that. Avoid drinking alcohol. Steer clear of second-hand smoke (or god forbid, first-hand). Don’t drink too much caffeine. Consult a physician on every medication you take, whether over-the-counter or prescription. Don’t eat sushi. Skip unpasteurized cheeses. Think twice before you get on a roller coaster.
But one thing no one says to you is this: don’t drive or ride in a personal motor vehicle if you can avoid it. Or at least, no one said it to me. No one told me the proper way to wear a seatbelt while pregnant, either.
But according to Professor Hank Weiss, of the University of Otago in New Zealand, the dangers to pregnant women and fetuses are great enough that doctors should consult with expectant mothers about the risk of driving as a matter of routine.
Weiss’s ongoing analysis of data on maternal crash injury risk suggests that when it comes to fetal mortality, the danger of getting in a car may be similar to that of smoking or drinking. “That was looking at the number of deaths attributed to those in the United States,” says Weiss, who is director of the Injury Prevention Research Unit at the university. “It’s loose, but it’s the same order of magnitude.” Being involved in a motor vehicle crash can also result in complications such as prematurity and placental abruption. The magnitude of the problem is likely far greater than the numbers show, Weiss says, because many cases – especially those involving early pregnancy – are not recorded in a way that is accessible to researchers.
And yet automobile use is such an ingrained part of our culture that we rarely think of it as the public health issue that it really is, even when it comes to the particularly vulnerable population of pregnant women. That remains true even in the most high-profile and extreme cases, such as the recent death of a young couple in New York City whose livery cab was hit by an apparently speeding driver, and whose son died after being born prematurely as a result of the crash.
Weiss has been studying the risks posed to pregnant women and fetuses by motor vehicle trauma for more than 20 years. His most recent work, published in the journal of the Australasian Epidemiological Association (paywall), looks at statistics in New Zealand, where 21 fetal and early neonatal deaths were attributed to motor vehicle crashes between 1997 and 2007.
Weiss notes in his paper that New Zealand has one of the highest motor vehicle ownership rates in the world, trailing only Portugal and the United States, and that from the early 1990s to the mid-2000s, the average distance driven by women age 15-39 increased by 40 percent. His conclusion?
Foetal death and injury due to maternal injury is a hidden but important component of child injury mortality in New Zealand and elsewhere. The problem remains hidden because of the way foetal trauma is coded in vital statistics and the lack of pregnancy status recorded in crash and injury surveillance systems. More attention needs to be directed to reporting and prevention of maternal injuries and adverse foetal outcomes.
In the United States, the issues are similar. According to a paper published by Weiss and his colleague Catherine Vladutiu in the American Journal of Lifestyle Medicine in 2011, pregnant women are more at risk from motor vehicle crashes than any other type of trauma, but reliable data is still hard to come by:
Motor vehicle crashes during pregnancy are the leading cause of traumatic fetal mortality and serious maternal injury, morbidity, and mortality in the United States, injuring approximately 92 500 pregnant women each year. Little is known about the circumstances surrounding these crash events and the maternal characteristics that may increase women’s vulnerability to crash-related injuries during pregnancy. Even less is known about the effects of crashes on fetal outcomes.
“We’ve created a built environment that encourages much more auto use,” says Weiss. At the same time, more and more women of child-bearing age have entered the workforce and are out on the road commuting, using the mode of travel most common in many developed nations.
But although pregnant women’s exposure to motor vehicle crashes has increased, the public health message has lagged behind. Weiss doesn’t anticipate that we’ll be seeing warning labels about driving while pregnant on cars anytime soon, similar to the ones that hang at establishments serving alcohol, and he doesn’t think that type of warning makes a meaningful impression, anyway.
“It’s more effective if it comes from a health care provider,” he says. “It should involve clinicians and direct counseling. It should be on the list of things that women are told to think about.”
For most women in an autocentric society, Weiss says, not driving isn’t an option. That doesn’t mean that their risk can’t be significantly reduced.
First of all, he says, pregnant women should be counseled always to wear a seatbelt, and how (with the belt snug over the hips). They should be assured that airbags are safe for pregnant women in crashes and should not be deactivated. If at all possible, they should avoid driving at night or in bad weather, when the risk of a crash is highest. Driving on roads with lower speeds is better, because low-speed crashes are exponentially less traumatic than high-speed ones.
And pregnant women should simply try to drive and ride in cars less. Maybe a woman’s partner can be the one to make the trip to the grocery store. Maybe she can try to use public transportation for at least some of the duration of her pregnancy. Maybe she should consider staying at home and watching a movie on Saturday night instead of hopping on the highway for a trip to the mall.
Such measures might seem radical in an environment where car use is so casually accepted and incorporated into everyday life, but considering the lengths women go to in order to reduce risk to their developing children in other ways, would it really be such a stretch to add these considerations?
Weiss looks at the issue through a purely statistical lens. “If you can cut your driving miles in half, you cut your risk in half,” he says. “We have very few public health interventions that have that kind of effect.”