Trauma is one of the most common reasons for emergency room visits during pregnancy. The exact incidence is unknown, although trauma is estimated to complicate approximately 1 in 12 pregnancies (Hill, 2008). Trauma is also the leading nonobstetric cause of maternal death. In some reports, it accounts for up to 20 percent of all maternal mortalities (Fildes, 1992; Kuhlmann, 1994). As perspective, this represents a larger proportion than the combined mortality rates of several well-known obstetric causes. Of specific events, Figure 17-1 shows the estimated incidences for several types of trauma suffered by gravidas compared with nonpregnant women.
FIGURE 17-1
Estimated incidence of injury by type of trauma during pregnancy. Rates are reported per 100,000 live births in pregnancy and per 100,000 women in the nonpregnant cohort. Rates for nonpregnant women were calculated using 2013 U.S. data from the Centers for Disease Control and Prevention Web-based Injury Statistics Query and Reporting System (WISQARS) (2015) when not available from the literature. MVC = motor vehicle crash.
The link between maternal injury and adverse pregnancy outcome is well recognized (Weiss, 2002). Most pregnancy complications directly correlate with the trauma severity, although even minor trauma may be linked to serious obstetric complications. Of sequelae, trauma has been associated with increased incidences of spontaneous abortion, placental abruption, preterm premature rupture of membranes, preterm birth, uterine rupture, cesarean delivery, and stillbirth (Pak, 1998; Pearlman, 1990; Schiff, 2002b, 2005). Specifically, pregnant women admitted for trauma but not delivered face an associated 2.7-fold increased risk of preterm labor, a 1.5-fold increased risk of abruption, and a fourfold increase in the risk of maternal death compared with noninjured controls (El Kady, 2004).
Fetal morbidity and mortality similarly may follow trauma during pregnancy. Each year almost 4000 fetal losses in the United States will result from motor vehicle crashes (El Kady, 2004). In these deaths, placental abruption is a major contributing factor (Shah, 1998). Only approximately 0.4 percent of women will require admission for trauma during pregnancy, but of those who do, almost one third will deliver during their hospitalization (John, 2011; Kuo, 2007). Thus, many of the consequences for these neonates derive from their preterm birth.
Pregnancy per se does not appear to increase the morbidity or mortality rate attributed to trauma. It may even contribute to a lower adjusted mortality rate (Ikossi, 2005; John, 2011). However, the pattern and severity of the injury may be modified by the qualities of the gravid uterus (Shah, 1998).
Management of a gravida and her fetus is complex. Thus, a multidisciplinary approach is often required to address the challenges posed by trauma in pregnancy. Ideally, experts in neonatology, anesthesiology, radiology, labor and critical care nursing, surgery, and obstetrics are available for consultation.
Pregnancy leads to several maternal anatomic alterations and physiologic adaptations that should be considered during evaluation of the gravida following trauma. During pregnancy, the maternal baseline heart rate rises by 10 to 15 beats per minute (bpm). Cardiac output is also estimated to increase by 30 to 40 percent to compensate for the augmented demand of the uterus and developing fetus (Tsuei, 2006). Specifically, the uterus at term may require up to 20 percent of the entire maternal cardiac output. Additionally, the red blood cell mass grows by 20 to 30 percent, and the plasma volume expands by 50 percent. In the first half of pregnancy, blood pressure tends to decline yet rises in later months. For these reasons, maternal hemorrhage may go unrecognized because altered vital signs may not develop until 30 to 35 percent of maternal blood volume has been lost (Marx, 1965). Notably, a nonreassuring fetal heart rate tracing that reflects diminished uterine blood flow may manifest before abnormal maternal signs are noticeable. Tracing changes may include a loss in fetal heart rate variability, late decelerations, or bradycardia.
Of other maternal hematologic changes, elevated concentrations of clotting factors lead to an expected hypercoagulable state in pregnancy. Accordingly, immobility following trauma in pregnancy may exacerbate the risk of venous thromboembolism (VTE). Moreover, VTE risks that are normally associated with orthopedic trauma are accentuated.
Pulmonary changes are also expected in the gravida. In late pregnancy, the resting diaphragm is elevated approximately 4 cm because of the enlarged uterus. This encroachment changes several measured lung volumes. The most significant ones are reductions in functional residual capacity and its subcomponents, expiratory reserve volume and residual volume. Minute ventilation also rises during pregnancy. This stems from an increased tidal volume rather than an increased respiratory rate, which is not appreciably altered during pregnancy. In addition, oxygen uptake and basal metabolism are elevated. The accentuated minute ventilation leads to lower PCO2 values and a compensated state of metabolic alkalosis (Table 17-1).
Additional maternal adaptions to pregnancy develop in other systems. The gastrointestinal tract has decreased motility as an effect of both compression and hormonal influence. Esophageal sphincter tone is diminished, and gastric emptying time is lengthened. These changes raise aspiration risks and demand preventive measures should tracheal intubation become necessary. Prevention is discussed in Chapter 19 (p. 308).
Unique changes to the gravid uterus can affect trauma management. First, uterine size plays a role. Namely, until approximately 12 weeks’ gestation, the uterus is a pelvic organ. By 20 weeks, the fundus has reached the level of the umbilicus and tends to reach the costal margins at approximately 36 weeks (Fig. 15-1, p. 245). These clinical landmarks are important when considering the possibility of fetal involvement at different gestational ages in cases of trauma.
Second, growth in uterine size and bulk can also exert significant pressure on abdominopelvic veins, especially the inferior vena cava. In pregnant women, the supine position may compromise venous return by up to 30 percent in the third trimester. Therefore, after 20 weeks’ gestation, every effort is made to laterally displace the uterus during an evaluation for trauma. Repositioning can be effected by manually elevating and rotating the right side of the woman’s torso. This position is then braced by a foam wedge or blanket roll. For those patients on a back board out of concern for a spinal injury, the right side of the board can be similarly lifted and braced (Kortbeek, 2008).
Third, these uterine size changes of pregnancy may also alter the expected injury pattern. For example, Elliot (1966) reported that serious retroperitoneal injury was more common in pregnant than nonpregnant women. Other authors report that bowel injury may be less common in gravidas suffering trauma. This may result from the gravid uterus displacing bowel up and under the more protective rib cage or laterally to the flank (Elliott, 1966).
Last, changes in uterine and placental tone respond to traumatic forces differently. The uterine wall has some elasticity, unlike the rather inelastic placenta. Thus, blunt trauma may only indent the uterine wall and displace amnionic fluid. However, the placenta deforms less easily, which makes it susceptible to separation with subsequent abruption.
In this chapter, the causes of trauma are divided into unintentional and intentional groups. Unintentional trauma includes motor vehicle crashes, slips and falls, burns, electric shock, and accidental poisoning. Intentional trauma encompasses domestic/intimate partner violence, penetrating trauma, suicide, and homicide.
The distribution of trauma by trimester appears to be similar among most cases of intentional and unintentional trauma (Tinker, 2010). However, slips and falls may be the exception. According to large, population-based cohort studies, these are more common in the third trimester (Schiff, 2008). Of risk factors, alcohol consumption, smoking, and drug use appear to be greater among women who report suffering a traumatic injury during pregnancy. Women noting injuries are also more likely to work outside the home. Of other risks, maternal seizure disorders raise the risk of trauma threefold (Tinker, 2010).
Intentional trauma is more commonly reported among women carrying fetuses of uncertain paternity or who describe their pregnancy as unwanted (Tinker, 2010). African American and Hispanic women are not only more likely to experience trauma in pregnancy. These groups are more likely to experience death from homicide during this time (Dannenberg, 1995; Ikossi, 2005).
Of trauma types, unintentional trauma accounts for a large portion of major injury during pregnancy (Schiff, 2002b). According to one review, as many as 90 percent of all cases of maternal injury are unintentional (Tinker, 2010). Of unintentional trauma, motor vehicle crash is reported by some to be the most frequently encountered form. Others state that slips and falls have a higher incidence during pregnancy (Tinker, 2010; Weiss, 2008).
Pregnant women involved in motor vehicle crashes (MVCs) can suffer both physical and emotional trauma. MVCs are one of the most common mechanisms by which pregnant women suffer blunt abdominal trauma. The overall incidence during pregnancy varies. One study approximates that 7 in every 100,000 pregnant women will experience a life-threatening injury during an MVC (Weiss, 2002). In another estimate by Kvarnstrand and associates (2008), MVCs occur in 207 of every 100,000 pregnancies and have an associated maternal mortality rate of 1.4 per 100,000 pregnancies. The risk of antepartum stillbirth is increased nearly fourfold, thus making MVC one of the leading causes of maternal and fetal mortality. Of all pregnant women involved in an MVC, up to 87 percent of this group receives some sort of medical care (Whitehead, 2013). MVCs are responsible for approximately 3.5 of every 1000 maternal admissions to the hospital. The vast majority of these admissions are after 20 weeks’ gestation (Vivian-Taylor, 2012).
Of risks for MVC, even among pregnant women, the use of intoxicants is a factor. In one report, 43 percent of pregnant women evaluated at a major trauma center following an MVC tested positive for an intoxicant (Ikossi, 2005; Patteson, 2007).
Seatbelt use has consistently been linked with higher survival rates after an MVC. Pregnant women may be hesitant to use seatbelts or use them incorrectly, especially during the third trimester. One unfounded belief is that seatbelt use may harm the uterus or the fetus during an accident. However, ejection from the vehicle is associated with a 32-fold increased risk of fetal death, a sixfold higher risk of placental abruption, and greater severity of maternal trauma (Fig. 17-2). Maternal consequences included severe head injury and maternal death (Aboutanos, 2008; Crosby, 1971; Curet, 2000). Lack of a seatbelt during an MVC doubles the risk of excessive maternal bleeding (Hyde, 2003). Preterm delivery is another complication, and gravidas not wearing a seatbelt are twofold more likely to deliver within 48 hours after an MVC. Such deliveries can be complicated by delivery of a low-birthweight or stillborn neonate (Wolf, 1993).
In both front and rear collisions, maternal impact against the steering wheel can be avoided with proper seatbelt use (Motozawa, 2010). The shoulder harness of the seatbelt should course over the collarbone between the woman’s breasts, and the lap belt should lie beneath the pregnant abdomen (Fig. 17-3) (Brown, 2009). In experiments done in near-term nonhuman primates, the use of both a lap and a shoulder harness as opposed to lap belt alone can lower fetal loss rates from 50 to 12.5 percent (Crosby, 1972). In contrast, if the lap belt is placed over the gravid uterus, the injury risk during an MVC may be exacerbated (Brown, 2009).
FIGURE 17-3
Proper seatbelt placement. The shoulder harness courses over the collarbone between the woman’s breasts. The lap belt lies under the pregnant abdomen. (Reproduced with permission from Cunningham FG, Leveno KJ, Bloom SL, et al (eds): Critical care and trauma. In Williams Obstetrics, 24th ed. New York, McGraw-Hill Education, 2014a.)
Proper seatbelt use is likely not stressed sufficiently during prenatal care. In one study, only half of patients noted receiving counseling regarding seatbelt use from their prenatal care provider (Sirin, 2007). Perhaps, as a result, the use of seatbelts during pregnancy has been reported to be as low as 21 percent (Chibber, 2015).
Many studies indicate that air bags are lifesaving in high-speed MVCs. However, the force and speed with which air bags deploy is substantial. Calculated deployment speeds of close to 200 miles per hour (mph) are cited as potential causes for concern in pregnancy (Bard, 2009). That said, no consistent evidence shows that airbag deployment during pregnancy raises the risk of adverse outcomes. In one investigation, air bag deployment after an MVC was not associated with an increased risk of placental abruption (Metz, 2006). Moreover, although some registries list abruption rates as high as 57 percent with air bag deployment, this is more likely related to the severity of the crash than deployment of the air bag (Luley, 2013). National Highway Traffic Safety Administration (2015) guidelines currently state that pregnant women should sit as far from the airbag as possible. This is a dynamic process that warrants seat adjustment with increasing abdominal girth. If a steering wheel offers a tilt option, the wheel is angled more toward the breast bone than the abdomen.
Several adverse pregnancy outcomes are linked to car crashes. Placental abruption may arise from the combination of several forces. Direct trauma from the steering wheel can clearly lead to placental separation. However, the lack of direct trauma does not eliminate the risk of abruption. When traveling at speeds exceeding 30 mph, an impact and sudden stop can throw the uterus forward and generate 550 mm Hg of pressure (Fig. 17-4). This motion builds both negative pressure and a contrecoup effect. These two mechanisms combined with the maternal body folding over the abdomen are sufficient to create almost 600 mm Hg of intraabdominal pressure (El Kady, 2007). These resulting forces are powerful enough to cause placental shearing and subsequent abruption (Reis, 2000).
FIGURE 17-4
Mechanism for placental abruption in motor vehicle collision. Forward momentum of the mother is seen early in the collision and forces her to wrap over the uterus. This is followed by a contrecoup, in which forces are directed backward. During each phase, tremendous intraabdominal pressure is generated that can lead to abruption.
The largest studies indicate that women involved in severe MVCs are at high risk of complications. Among critically injured women, placental abruption can be seen in as many as 40 percent of cases (Ali, 1997). Pregnant women involved in MVCs also carry a greater risk for cesarean delivery (Schiff, 2005). Loss of consciousness and pelvic fracture, indicating more severe trauma, are risk factors for poor fetal outcomes including fetal death after an MVC (Aboutanos, 2008). Although pregnant women tend to have less severe trauma after MVC, they are 50 percent more likely to require genitourinary surgery than nonpregnant women involved in motor vehicle crashes (Azar, 2015; Ikossi, 2005).
Of fetal consequences, the risk of preterm birth and perinatal death is increased only if delivery occurs immediately following a crash (Vivian-Taylor, 2012). Immediate delivery after an MVC is uncommon with an estimated rate of 0.4 percent in pregnancies under 20 weeks’ gestation and 3.5 percent in those after 20 weeks’ (Reis, 2000). In a study evaluating more than 600,000 women, Vivian-Taylor and associates (2012) found that pregnant women who were involved in car crashes and who remained undelivered after this event had similar maternal and fetal outcomes compared with women not involved in such crashes.
These are responsible for 17 to 39 percent of trauma-related emergency room visits during pregnancy (Dunning, 2010). Greater joint laxity and weight gain can shift the center of gravity and alter gait. Dynamic postural stability declines with pregnancy, especially during the third trimester (McCrory, 2010). Individually or combined, these changes can predispose gravidas to slips and falls.
As many as one in four pregnant women are estimated to fall at least once while pregnant. Among those who fall, 35 percent did so two or more times. Nearly 60 percent of women experiencing a fall will have a related injury, and one in five of these will require restricted activity following the fall (Dunning, 2010). Schiff (2008) found an incidence of 49 fall-related hospitalizations per 100,000 deliveries. Of these pregnant women, 79 percent were in their third trimester. Fracture of the lower extremity is the most commonly associated harm.
Most falls are indoors, and up to 39 percent will be related to falling from stairs (Dunning, 2010). In a prospective trial conducted by Vladutiu and coworkers (2010), the incidence of injury in gravidas was 4.1 cases per 1000 exercise hours and 3.2 cases per 1000 physical activity hours. Most of these injuries were attributed to falls. Dunning and colleagues (2003) found that 6.3 percent of all employed pregnant women experienced a fall at work. Major risk factors included carrying heavy objects, hurrying, or walking on slippery floors.
Pregnant patients admitted to the hospital after a fall carry elevated risks for adverse pregnancy outcomes. Compared with a control group that was randomly selected, gravidas who had fallen had a 4.4-fold increased risk for preterm labor, an eightfold increase in placental abruption rates, a twofold greater risk for fetal distress, a 1.3-fold increased cesarean delivery rate, a twofold greater risk for labor induction, and a threefold rise in rates of fetal hypoxia (Fig. 17-5) (Schiff, 2008).
The true incidence of burns during pregnancy is difficult to ascertain, as the literature is mostly composed of case reports and case series. Among reproductive-aged women, estimated incidences lie between 1.3 and 7 percent (Akhtar, 1994; Karimi, 2009). In reproductive-aged women in Iran, Maghsoudi and associates (2006) found the incidence of burns among gravidas was 0.17 percent compared with 2.6 percent per 100,000 person-years. From this data, pregnancy per se does not seem to be a risk factor for burns. Moreover, pregnancy does not appear to independently alter maternal survival after severe burns (Akhtar, 1994).
However, several adverse pregnancy outcomes do appear to be increased in gravidas suffering burns. Of clinical characteristics, the burn depth and the total body surface area (TBSA) burned has the greatest affect on both maternal and fetal outcomes. Specifically, in one series, burns covering 60 percent or more of the woman’s TBSA carried both maternal and fetal mortality rates close to 100 percent (Akhtar, 1994). Sepsis is a major contributing factor to this outcome (Chama, 2002). Another significant risk factor for both maternal and fetal mortality is smoke inhalation (Karimi, 2009). Maternal age or the trimester of pregnancy during which the burn occurs does not appear to affect maternal or fetal outcomes. Severe burns during the first trimester have been associated with spontaneous abortion, which is probably secondary to ensuing infection (Jain, 1993). Most of these losses are within 10 days of the burn (Chama, 2002). In another series, intrauterine fetal demises linked to severe burns occurred within 24 hours in 74 percent of cases (Akhtar, 1994). Thermal injury also appears to increase the risk of preterm birth (Rode, 1990). This may be secondary to the severity of the burn, and its effect on maternal health.
Cases of electric shock during pregnancy are infrequent. Isolated case reports have linked electric shock to spontaneous abortion, placental abruption, fetal burns, maternal cardiac arrhythmias, and stillbirth (Goldman, 2003; Yoong, 1990). During pregnancy, the main factor threatening fetal well-being is the electric current path through the mother’s body. A vertical current, as in hand-to-foot or head-to-foot pathways, may course through the uterus and harm the fetus (Sparic, 2016).
Severity of the shock also proportionally affects fetal outcome. Among 15 cases of severe electric shock during pregnancy, the fetal mortality rate was 73 percent (Fatovich, 1993). In a case series evaluating 13 cases in which gravidas were struck by lightning, the stillbirth rate was 50 percent. One neonate died a few hours after delivery (Garcia Gutierrez, 2005). In contrast, of 28 women who suffered minor electric shock between 4 and 36 weeks’ gestation, most of their newborns (94 percent) had favorable outcomes. No differences were noted in mode of delivery, birth weight, or gestational age at delivery compared with pregnant controls (Einarson, 1997).
The incidence of accidental poisoning during pregnancy is uncertain but probably low. In a review of more than 400 maternal deaths, only one case was secondary to accidental poisoning (Gissler, 2007). Notably, case reports describe hospitalized pregnant women who received accidental overdoses of medications from epidural and magnesium infusion pump errors (McDonnell, 2010; Patel, 2011).
Pregnant women who experience intentional trauma are at significant risk for maternal-fetal morbidity and mortality. The most common form of intentional trauma experienced by gravidas is domestic violence (DV), which is also known as intimate-partner violence (IPV).
IPV is a serious problem during pregnancy. Its true incidence is difficult to assess and varies depending on the population examined and definitions used. Reported rates range from 3 to 57 percent (Arslantas, 2012; Beydoun, 2011; Koenig, 2006; Silva, 2011; Stockl, 2012). In a postpartum survey of more than 100,000 women, Cheng and coworkers (2015) found an IPV rate during pregnancy of 6.4 percent. The IPV rate may rise during pregnancy, especially among high-risk groups. Helton and associates (1987) noted that as many as 1 in 12 inner-city women are victims of IPV. In a prospective Australian study, 40 percent of women who reported depressive symptoms 3 to 12 months postpartum also disclosed suffering IPV (Woolhouse, 2012).
It can be difficult to detect IPV during pregnancy. Victims often present with nonspecific complaints during emergency room or routine prenatal visits. One of the first signs may be depression or substance abuse. Often the perpetrating partner insists on being included in any interaction with a health-care provider.
Maternal risk factors for IPV are numerous. They include low socioeconomic status, low education-level attainment, maternal or intimate-partner substance abuse, unintended pregnancy, experiencing IPV before pregnancy, witnessing violence as a child, and unmarried status (Castro, 2003; Martin, 1996; Meuleners, 2011; Quinlivan 2001; Umeora, 2008).
IPV has been linked with an increased rate of spontaneous abortion, neonatal intensive care unit (NICU) admissions, and low birthweight (Fanslow, 2008; Jagoe, 2000; Yang, 2006; Yost, 2005). In addition, the risk of preterm birth is estimated to rise threefold (Rodrigues, 2008). Women reporting IPV in the year prior to pregnancy are also at increased risk for similar adverse outcomes (Silverman, 2006). Several studies have reported a strong association between IPV and peripartum depression (Ludermir, 2010; Urquia, 2011; Woolhouse, 2012). This included a prospective study that followed more than 13,000 women and infants (Flach, 2011).
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