Increased automobile travel by pregnant women increases the likelihood of fetal injury or pregnancy complications from crashes, but relatively little is known about the factors involved in such outcomes. Studies have been limited by consideration of only fetal mortality or only pregnant women treated at hospitals following crashes. Hyde and colleagues used statewide databases on crashes and pregnancy outcomes to determine the effect of crashes during pregnancy and the effect, if any, of seatbelt use.

The authors used data from police records, birth certificates, and certificates of fetal death from Utah between 1992 and 1999. These data were only able to identify pregnant women drivers and not all pregnant women involved in vehicle crashes. The data were further limited to crashes occurring on public roadways and crashes resulting in injury, fatality, or at least $1,000 in property damage. The pregnancy outcomes were limited to those recorded on birth or fetal death certificates and included abruptio placentae, fetal distress, birth weight less than 2,500 g (5 lb, 8 oz), birth before 37 weeks’ gestation, excessive maternal bleeding, delivery within 48 hours of the crash, cesarean delivery, fetal mortality, and abnormal conditions such as seizures, birth injury, or assisted ventilation.

Of the 322,704 live singleton births during the study period, 8,938 (2.8 percent) were linked to a motor vehicle crash during pregnancy. Women drivers who crashed during pregnancy were slightly younger, more likely to smoke, more likely to have fewer previous births, and more likely to have begun prenatal care during the first trimester than pregnant women who were not involved in crashes. Overall, women who crashed had pregnancy outcomes similar to outcomes of those who did not, but the outcomes varied considerably by seatbelt use. The 12 percent of drivers who crashed while not using a seatbelt differed significantly from the 80 percent who used a seatbelt. (It was not possible to ascertain seat-belt usage for the remaining 8 percent.) Those who did not use a seatbelt were younger, had less education, used more tobacco and alcohol during pregnancy, and usually did not begin prenatal care during the first trimester.

Women who did not use a seatbelt at the time of a crash were significantly more likely to have excessive bleeding during labor and increased rates of low birth weight, fetal distress, and cesarean delivery than women who crashed while wearing a seatbelt. Pregnant women who were wearing a seatbelt at the time of a crash were no more likely to experience adverse outcomes than pregnant women who were not involved in a crash. Maternal injury was the principal cause of the 45 fetal deaths associated with crashes after 20 weeks’ gestation that were recorded during the study.

The authors conclude that nearly 3 percent of births can be linked to a significant automobile crash in which the pregnant mother was the driver. If a seatbelt is worn, pregnancy outcomes do not appear to be significantly altered by crashes. Conversely, pregnant drivers who do not use a seatbelt are more likely to experience significant bleeding and to have a low-birth-weight infant, and three times more likely to have a fetal death than pregnant women who crash while wearing a seatbelt.

editor's note: The list of questions family physicians are supposed to ask for “prevention” keeps getting longer. If we screened for and counseled on everything the experts recommend, there would be little time to address the presenting complaint, let alone deal with all the other agendas of a typical office visit. Nevertheless, seatbelt use is a “high payoff” item for all patients, especially pregnant women. It is important to convey the message in a supportive and positive manner and not to “nag.” The concept of prospective care always seems much more positive than “prevention.” The risk factors, including not using a seatbelt, tend to cluster in our most vulnerable patients, as shown in this study. These patients need our extra time and support to reduce their burden of risk. The rewards could be substantial.—a.d.w.