TUESDAY, Oct. 16, 2001 (HealthDayNews) -- Of all the ways pregnant women are injured, car wrecks are the deadliest for their unborn babies, a new study says.
What's more, researchers estimate that some 370 fetuses die each year in accidents on American roads, more than twice as many as the 180 infants killed annually in car crashes. For women 20 weeks or more into gestation, trauma caused by a collision accounts for about 80 percent of all lost pregnancies, the study finds.
When in a car, "the fetus takes on the risk of the mother" and then some, says Dr. Harold Weiss, a University of Pittsburgh traffic safety expert and lead author of the paper, which appears in the Oct. 17 issue of The Journal of the American Medical Association.
The study looked at fetal death certificates from 16 states, including California, Texas, Pennsylvania and New Jersey, between 1995 and 1997. Together the states had about 55 percent of all live births in the United States during the period and had roughly 15,000 fetal deaths a year.
Based on the 80 fetal deaths the researchers identified in the 16 states they studied, they estimated the national annual fetal death rate at 370.
Direct trauma to the fetus is rarely responsible for the fatalities, experts say. Rather, the deaths typically occur when the placenta is torn from the uterus or is otherwise damaged by the force of impact, depriving the fetus of oxygen and other nutrients and necessitating immediate delivery.
In fact, because states almost never record a fetal deaths unless the baby is delivered, miscarriages of early pregnancies after an accident aren't usually included in road fatality counts, Weiss says. As a result, the true number of fetal deaths linked to driving may be even greater.
"Anything under 20 weeks is almost never reported in states' fetal death certification, so we know nothing about the numbers below 20 weeks, and I have no way to even estimate" the rate of deaths for these fetuses, Weiss says. "They may be at less risk because they're smaller, but they may be at greater risk because they're smaller."
Weiss and his colleagues found that approximately 2 percent of pregnant women in the United States are involved in car crashes each year.
The risks for teen mothers was roughly five times that for women over 34, reflecting an increased likelihood that younger people will be involved in auto accidents, the researchers say.
Mothers were killed in crashes far less often than their unborn babies, the study found.
Car crashes were implicated in 2.3 fetal deaths per 100,000 live births each year during the study, the researchers say. In three of the 16 states, more fetuses died in car wrecks than infants. Car crashes account for 82 percent of trauma-related fatalities to fetuses, with other sources of trauma lagging well behind. Deaths from gunshots made up 6 percent of cases, while falls accounted for 3 percent of fetal deaths.
"Wearing a seat belt is the way to go," says Kathleen Klinich, a mechanical engineer at the University of Michigan in Ann Arbor who studies motorist safety. Klinich and her colleagues are developing MAMA-2B, a prototype dummy that will measure the forces that affect pregnant women in a car crash.
Despite erroneous reports to the contrary, seat belts rarely harm pregnant women in a collision, Klinich says. Crash investigations and mock wrecks reveal that both mother and fetus do better when the woman wears a snugly fitting, three-point seat belt that crosses her shoulder and lap. Evidence suggests that pregnant women can reduce the risk of harm to the placenta during a crash by wearing the lap portion of the belt as low as possible, preferably near the legs, she says.
Rae Tyson, a spokesman for the National Highway Traffic Safety Administration (NHTSA), which helped fund the Pittsburgh research, says the problem "is an area of concern" for the agency.
NHTSA has tried to educate motorists on how to drive safely during pregnancy, advising always to wear a seat belt and not to disconnect the air bags, Tyson says.
What To Do
So how else can pregnant women protect their internal passengers?
"One of the recommendations that I generally try to make is that people should try to get the most crash-safe car that they can afford," Weiss says. Another way is to drive less. "Obviously, people are not going to stop driving altogether, but cutting time in a vehicle in half would reduce the risk [of fetal death] by half," he says.
Take public transportation whenever possible, combine several little trips into one big one and invite people over instead of going to them. "At first glance it seems difficult, but I really think there are a lot of things people can do to reduce their crash risk," he says.
Most important of all, says Weiss, is to wear your seat belt.
For more information on how to drive safely during pregnancy, try ePregnancy.com.
For more traffic safety tips, try the National Highway Traffic Safety Administration.
