Pregnant Women Urged to Buckle Up

April 2, 2008 -- Nearly 200 fetuses are lost each year in the U.S. because of pregnant women who don't wear seat belts or wear them improperly, a University of Michigan study suggests.

That's more than the number of annual infant deaths in car crashes, and more than the annual number of kids who die in bicycle accidents, says Mark D. Pearlman, MD, vice-chairman of obstetrics and gynecology at the University of Michigan Health System.

Pearlman says many pregnant women, and even some doctors, worry that in the event of a car crash, seat belts themselves will injure the fetus of a woman who's buckled up. Is that what happens? Pearlman and colleagues conducted in-depth studies of 57 car crashes involving pregnant occupants.

"An 84% reduction in risk of adverse fetal outcomes is obtained by properly wearing a seat belt," Pearlman and colleagues find. "Unbelted pregnant occupants sustain an estimated 62% of all fetal losses in motor vehicle crashes."

Four out of five pregnant women already wear seat belts properly. If all pregnant women did so, the researchers calculate it would save the lives of 192 fetuses a year.

In a car crash, the study shows, injury to the mother is the main risk to the fetus. Seat belts offer the most protection to fetuses in crashes where mothers sustain the least injury -- that is, in less-severe wrecks.

But in these less serious wrecks, the benefit of seat belts is huge.

Pearlman and colleagues calculate that in a car going about 20 miles per hour, a pregnant woman properly wearing a seat belt has a 12% chance of serious fetal injury. That risk goes up to 70% -- in the same crash -- for women not properly buckled up.

"It's very clear, based on this study, that pregnant women should buckle up every single time they're in a vehicle," Pearlman says.

The report appears in the April issue of the American Journal of Obstetrics & Gynecology.