Original concerns regarding injuries caused by airbag deployment have been somewhat allayed (Luley, 2013; Matsushita, 2014). One study included 30 such women from 20 to 37 weeks' gestation whose airbag deployed in accidents with a median speed of35 mph (Metz, 2006). A third did not use seat belts, and there was one fetal death from the single case of placental abruption. In a retrospective cohort study that included 2207 pregnant women in crashes with airbag deployment, perinatal outcomes were not clinically diferent from 1141 controls without airbags (Schif, 2010). Importantly, 96 percent of both groups used seat belts. Thus, it appears that injuries with airbag deployment are related to the severity of the crash (Mendez-Figueroa, 2016).
Some other common causes of blunt trauma are falls and aggra vated assaults. In the California review reported by El Kady and associates (2005), intentionally inflicted injuries were present in approximately a third of pregnant women who were hospitalized for trauma. Less common are blast or crush injury (Sela, 2008). With blunt trauma, intraabdominal injuries can be serious. Even so, bowel injuries are less frequent because of the protective efect of a large uterus. Still, diaphragmatic, splenic, liver, and kidney damage may also be sustained. Par ticularly worrisome is the specter of amnionic-fluid embolism, which has been reported with even mild trauma (Ellingsen, 2007; Pluymakers, 2007). Retroperitoneal hemorrhage is pos sibly more common than in nonpregnant women (T akehana, 2011).
Orthopedic injuries are also encountered with some regular ity (Desai, 2007). From the Parkland Hospital trauma unit, 6 percent of 1682 pregnant women evaluated had orthope dic injuries. his subset was also at increased risk for placen tal abruption, preterm delivery, and perinatal mortality. In a review of 101 pelvic fractures during pregnancy, there was a 9-percent maternal and 35-percent fetal mortality rate (Leggon, 2002). In another study of pelvic and acetabular fractures dur ing 15 pregnancies, there was one maternal death, and four of 16 fetuses died (Almog, 2007). Finally, head trauma and neu rosurgical care raise unique issues (Qaiser, 2007).
Perinatal death rates increase with the severity of maternal injuries. Fetal death is more likely with direct fetoplacental injury, maternal shock, pelvic fracture, maternal head injury, or hypoxia (Ikossi, 2005; Pearlman, 2008). Motor vehicle accidents caused 82 percent of fetal deaths from trauma. Death was caused by placental injury in half and by uterine rupture in 4 percent (Weiss, 2001).