Williams Manual of Pregnancy Complications, 23 ed.

CHAPTER 87. Trauma in Pregnancy

Trauma, homicide, and similar violent events are a leading cause of death in young women. According to the American College of Obstetricians and Gynecologists: Obstetric aspects of trauma management. Educational Bulletin No. 251, September 1988, as many as 10 to 20 percent of pregnant women suffer physical trauma.

TYPES OF TRAUMA IN PREGNANT WOMEN

Physical Abuse

Physical violence in pregnancy is linked to poverty, poor education, and use of tobacco, drugs, and alcohol. Abused women tend to stay with their abusers placing them at increased risk for intimate partner homicide. The woman who is physically abused tends to present late, if at all, for prenatal care. A number of adverse perinatal outcomes are increased in these women, including preterm birth, placental abruption, uterine rupture, and fetal death. The American College of Obstetricians and Gynecologists recommends universal screening for domestic violence at the initial visit, during each trimester, and at the postpartum visit.

Sexual Assault

The overwhelming majority of sexual assault victims are women and it has been estimated that approximately 2 percent of them are pregnant. Associated physical trauma occurs in about half of sexual assault victims. Psychological counseling for the rape victim and her family are extremely important. Screening for and treating sexually transmitted diseases must also be a part of the evaluation.

Automobile Accidents

At least 3 percent of pregnant women are involved in motor vehicle accidents. Vehicular crashes are the most common causes of serious, life-threatening, or fatal blunt trauma in pregnancy. They are also the leading cause of traumatic fetal deaths. Up to half of the accidents are associated with lack of seat belt use, and many of the deaths might be preventable with the use of three-point restraint seat belts. Shown in Figure 87-1 is the correct placement of the three-point restraint seat belt.

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FIGURE 87-1 Illustration showing correct use of three-point automobile restraint. The upper belt is above the uterus and the lower belt fits snugly across the upper thighs and well below the uterus. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)

Penetrating Injuries

Knife and gunshot wounds are the most common penetrating injuries and may be associated with aggravated assaults, suicide attempts, or attempts to cause abortion. The incidence of visceral injury with penetrating trauma is only 15 to 40 percent compared with 80 to 90 percent in nonpregnant individuals. When the uterus sustains penetrating wounds, the fetus is more likely than the mother to be seriously injured.

Burns

Fetal prognosis is poor with severe burns. Usually the woman enters labor spontaneously within a few days to a week, and she often delivers a stillborn infant. Contributory factors are hypovolemia, pulmonary injury, septicemia, and the intensely catabolic state associated with burns. Pregnancy does not alter maternal outcome compared with nonpregnant women of similar age. Maternal and fetal survival parallels the percentage of burned surface area. As the total burned body surface area reaches or exceeds 50 percent, both maternal and fetal mortality exceed 50 percent.

OBSTETRICAL COMPLICATIONS

Placental Abruption

Abruption complicates 1 to 6 percent of “minor” injuries and up to 50 percent of major injuries. Placental abruption is more likely in car accidents involving speeds over 30 mph. Shown in Figure 87-2 is the mechanism of acute deceleration injury resulting in placental abruption.

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FIGURE 87-2 Acute deceleration injury when the elastic uterus meets the steering wheel, and as it stretches, the inelastic placenta sheers from the decidua basalis. Intrauterine pressures as high as 550 mm Hg are generated. (Reproduced, with permission, from Cunningham FG, Leveno KJ, Bloom SL, et al (eds). Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010.)

Clinical findings with traumatic abruption may be similar to those with spontaneous placental abruption, as discussed in Chapter 35. A majority of women with traumatic abruption will complain of uterine tenderness; however, less than half will have vaginal bleeding. Traumatic abruptions are more likely to be concealed and associated with coagulopathy than nontraumatic abruptions. Importantly, uterine contractions may indicate partial separation of the placenta in an otherwise asymptomatic woman.

Uterine Rupture

Rupture is uncommon with blunt trauma and is found in less than 1 percent of severe cases. Rupture is more likely with a previously scarred uterus and is usually associated with a direct impact of significant force. Clinical findings may be identical to those for placental abruption.

Fetal-to-Maternal Hemorrhage

Life-threatening fetal-to-maternal hemorrhage may be encountered if there is considerable abdominal force associated with trauma, and especially if the placenta is lacerated. Some degree of bleeding from the fetal to maternal circulation is found in as many as 30 percent of pregnant trauma cases. In 90 percent of these cases, however, the fetal hemorrhage is less than 15 mL. This is not due to placental separation, because there usually is no fetal bleeding into the intervillous space. More likely this fetal hemorrhage is associated with a placental tear or “fracture” caused by stretching (Figure 87-3).

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FIGURE 87-3 A. Partial placental abruption with adherent blood clot. The fetus died from massive hemorrhage, chiefly into the maternal circulation. B. The adherent blood clot has been removed. Note the laceration of the placenta. C. Kleihauer–Betke stain of a smear of maternal blood after fetal death. The dark cells (4.5 percent) are fetal red cells, whereas the empty cells are maternal in origin.

Fetal Injury

The risk of fetal death with trauma is significant when there is direct fetoplacental injury, maternal shock, pelvic fracture, maternal head injury, or hypoxia. Fetal skull and brain injuries are the most common. These injuries are more likely if the head is engaged and the maternal pelvis is fractured on impact. Conversely, fetal head injuries, presumably from a contrecoup effect, may be sustained in unengaged cephalic or noncephalic presentations.

MANAGEMENT

With few exceptions, treatment priorities are directed toward the injured pregnant woman as they are for nonpregnant patients. Primary goals are evaluation and stabilization of maternal injuries. Basic rules are applied to resuscitation, including establishing ventilation and control of hemorrhage along with treatment for hypovolemia with crystalloid and blood products. An important aspect of management is deflection of the large uterus away from the great vessels to diminish their effect on decreased cardiac output.

Following emergency resuscitation, evaluation is continued for fractures, internal injuries, bleeding sites, as well as uterine and fetal injuries. If indicated, open peritoneal lavage should be performed in the pregnant woman. Penetrating injuries in most cases must be evaluated using radiography. Because clinical response to peritoneal irritation is blunted during pregnancy, an aggressive approach to exploratory laparotomy is recommended for abdominal trauma. Exploration is mandatory for abdominal gunshot wounds while close observation for selected stab wounds may be appropriate.

Cesarean Delivery

The necessity for cesarean delivery of a live fetus depends on several factors. Laparotomy itself is not an indication for cesarean delivery. Considerations include gestational age, fetal condition, extent of uterine injury, and whether the large uterus hinders adequate treatment or evaluation of other intra-abdominal injuries.

Fetal Heart Rate Monitoring

As for many other acute or chronic maternal conditions, fetal well-being may reflect the status of the mother. Even if the mother is stable, the use of fetal monitoring may be useful for diagnosis of placental abruption. If uterine contractions are less often than every 10 minutes within 4 hours after trauma, placental abruption is unlikely. Importantly, 20 percent of women who have more frequent contractions have an associated placental abruption. In these cases, fetal tachycardia and late decelerations are common.

Because placental abruption usually develops early following trauma, fetal monitoring is begun as soon as the maternal condition is stabilized. An observation period of 4 hours is reasonable with a normal fetal heart rate tracing and no other ominous signs such as contractions, uterine tenderness, or bleeding. Monitoring should be continued as long as there are uterine contractions, a non-reassuring fetal heart pattern, vaginal bleeding, uterine tenderness or irritability, serious maternal injury, or ruptured membranes.

Kleihauer–Betke Testing

Routine use of the Kleihauer–Betke or an equivalent test in pregnant trauma victims is controversial. Some investigators feel that the test is of little use in the setting of acute trauma, and electronic fetal monitoring and ultrasound are more useful in detecting fetal or pregnancy-associated complications. For the woman who is D-negative, administration of anti-D immunoglobulin should be administered, although this dose may be omitted if the test for fetal bleeding is negative.


For further reading in Williams Obstetrics, 23rd ed.,

see Chapter 42, “Critical Care and Trauma.”