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FRIDAY, Aug. 1, 2003 (HealthDayNews) -- If you drive during pregnancy, buckle up before you pull away from the curb.
That's the advice of researchers from the University of Utah, where a new study showed pregnant women who wear seat belts not only protect themselves, but their babies as well.
While many pregnant women believe the pressure of a seat belt on the abdomen might hurt the baby, nothing could be further from the truth, says study author Lisa Hyde.
"The take-home message from this research is that if you are driving while pregnant you must wear a seat belt. In the event of a car crash we found a marked increase in the potential for problems, for baby and mother, when the mother failed to buckle up," says Hyde, whose study appears in the August issue of Obstetrics and Gynecology.
Up to 2 percent of all babies born in the United States -- some 79,000 infants -- are involved in an automobile crash while still in the womb, according to research published last year in the journal Injury Prevention.
Although previous studies on pregnant drivers have been able to demonstrate the immediate consequences of crashes -- such as premature delivery -- Hyde says little was known about the effects of the crash on the baby later in the pregnancy.
In addition, because previous studies focused solely on pregnant drivers involved in car crashes, it was difficult to isolate which ensuing problems involving mother or child were crash-related, and which might be routine complications of pregnancy.
That's where Hyde says her study makes an important contribution.
"We compared the pregnancy outcomes of women in car crashes with and without seat belts, to pregnant women not involved in any car crashes, and in doing so found that seat belts really do make a difference," Hyde says.
The study data was gathered from the state of Utah general population database, which included police-recorded motor vehicle crash records, along with birth certificates and fetal death certificates for the years 1992 to 1999. During this time, there were 322,724 births, with 8,938 of the mothers -- 2.8 percent -- involved in a car crash during their pregnancy.
Using two methods of statistical calculation, the researchers compared the incidence of birthing complications among women in car crashes -- with and without seat belts -- to those among pregnant women not involved in crashes. Among the complications studied were low birth weight, premature delivery, fetal distress, excessive maternal bleeding and fetal death.
The result: The differences between women involved in car crashes who were wearing seat belts and women who had no car accidents was negligible, with virtually no statistically significant difference in the number of adverse pregnancy outcomes in the two groups.
However, when comparing the women in crashes who didn't wear seat belts to women who had no car accidents, the differences were dramatic.
"We found that women who crashed without the protection of a seat belt were 1.3 times more likely to have a low birth weight infant. They were also twice as likely to experience serious maternal bleeding during their pregnancy," says Hyde.
Hyde also reports that car crashes involving pregnant drivers who didn't buckle up resulted in fetal death nearly three times more often than in women who were wearing seat belts when their accidents occurred.
Currently, the American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant women wear seat belts in cars as well as on airplanes during their entire pregnancy.
The group also suggests lap belts be buckled low on the hipbone, below the belly, and never across the stomach. The use of shoulder belts is also recommended, with the suggestion that the strap cross over the center of the chest, and not under the arm.
Finally, ACOG experts say the belt should fit snugly, but not tight. And they warn women not to slip the upper portion of the belt off the shoulder, or allow any portion of it to hang loosely, or ride up too high on the belly. Doing so, they caution, can cause injury to your ribs or your abdomen.
However, ACOG also stresses that wearing no seat belt carries far more dangers -- a fact that Hyde says her study illustrates.
"The important thing to remember is that wearing a seat belt during pregnancy helps more than it harms," Hyde says.
For a guide to traveling during pregnancy, visit the U.S. Centers for Disease Control and Prevention. To learn more about pregnancy complications, check with The National Women's Health Information Center.