Seatbelts are pregnant drivers’ best bet to prevent auto injuries, study finds

Oct. 15, 2013
We’ve all heard it before: seatbelts save lives. For pregnant women, seatbelts could mean saving at least one life now and another in the very near future.

That’s the conclusion from an exhaustive study of 878,546 pregnant drivers between 16 and 46 years old, conducted by researchers at The University of North Carolina’s Gillings School of Global Public Health.

The study, “Adverse Pregnancy Outcomes Following Motor Vehicle Crashes,” published online Oct. 8 in the American Journal of Preventive Medicine, analyzed the nearly 900,000 pregnant drivers from North Carolina who gave birth to a single infant between 2001 and 2008.

Catherine J. Vladutiu, PhD, postdoctoral fellow in epidemiology at the Gillings School, led the research.

Blunt abdominal trauma directly and indirectly can harm fetal organs as well as shared maternal and fetal organ systems. Car crashes are responsible for most injuries requiring hospitalization during pregnancy, yet little is known about the relationship between auto accidents and their effects upon specific fetal injuries.

Investigators examined four main areas of fetal injury – preterm birth, placental abruption, premature rupture of the membranes and stillbirth. They found that, compared to women who were not involved in an auto accident, pregnant drivers had slightly elevated rates of preterm birth, placental abruption and premature rupture of the membranes after a single crash.

“Non-seat belt use and the lack of airbags were associated with elevated rates of selected adverse pregnancy outcomes,” Vladutiu said. “Most notably, the stillbirth rate following a crash involving an unbelted pregnant driver was almost three times as high as the stillbirth rate following a crash involving a belted pregnant driver.”

While previous studies had looked only at the link between one crash and adverse pregnancy outcomes, the new study also looked at women who had been involved in multiple motor vehicle collisions during their pregnancies. Following a second or subsequent crash, investigators found pregnant women had more highly elevated rates of preterm birth, placental abruption, premature rupture of the membranes and stillbirth. The investigators found that the rates of these unfavorable outcomes increased as the number of crashes increased.

While the new study offers greater insight than previously existing reports, more population-based studies with larger sample sizes are necessary to increase understanding of the effect of multiple crashes, seatbelts and airbags on pregnancy outcomes.

“Clinicians should be aware of these effects and should advise pregnant women about the risk of being in a crash and the long-term consequences that crashes can have on their pregnancies,” Vladutiu said. “Given the associations that were observed, a better understanding of the circumstances surrounding crashes during pregnancy is needed to develop effective strategies for prevention.”

Co-authors on the paper from UNC Gillings include Steve Marshall, PhD, professor of epidemiology and director of UNC’s Injury Prevention Research Center; Charles Poole, ScD, associate professor of epidemiology; and Carri Casteel, adjunct associate professor of epidemiology.

Gillings School of Global Public Health contact: David Pesci, director of communications, (919) 962-2600 or