Trauma during Pregnancy

April 2002, MERGINET - Accidental injury complicates approximately six to seven percent of all pregnancies. 1 Most are relatively minor. However, some can have devastating consequences for both the mother and the fetus. In a recent study of 85 pregnant women suffering varying forms of trauma during pregnancy, 31 percent had trauma significant enough to cause some transfusion of blood from the fetus to the mother. In addition, 9.4 percent of these patients had some degree of an abnormal separation of the placenta from the uterine wall (abruptio placenta). 2 Another study examined 205 cases of non-catastrophic trauma during the last half of pregnancy. It found that pregnancy-related complications occurred in 8.8 percent of patients. The most common complication was premature labor. However, abruptio placenta, fetal injury, and fetal death were also reported. 3 Accidents which initially appear relatively minor can cause serious injuries which can threaten the lives of both the mother and the fetus. The key to improved patient care of the pregnant trauma patient is early recognition and management by trained pre-hospital personnel. This article presumes the reader knows the normal anatomical and physiological changes of pregnancy; it focuses on trauma in conjunction with pregnancy and appropriate pre-hospital care for these patients.

Trauma in pregnancy, like trauma in the non-pregnant individual, falls into three injury categories: penetrating, non-penetrating, and thermal. Penetrating injuries involve such things as gunshot and stab wounds. Non-penetrating injuries (also called blunt trauma) typically are caused by falls and motor vehicle accidents. Thermal injuries are typically heat-related.

Penetrating trauma
Penetrating trauma in pregnancy usually results from either gunshot or stab wounds. Animal gore wounds, although rare in North America , do occur in developing countries and in certain rural areas. With penetrating trauma to the abdomen, the likelihood of an organ being hit is related to the relative size of the organ. Gunshot wounds to the abdomen of a non-pregnant individual will typically injure the small intestine, liver, colon, and stomach. Early in pregnancy the uterus is fairly small, but as the uterus enlarges, the likelihood of it suffering injury increases proportionately. Fortunately, there have been no maternal deaths from isolated gunshots to the uterus reported since 1912. 1 Low-velocity missiles which penetrate the abdominal wall, and strike the uterus transfer a significant amount of their energy to the relatively dense muscles of the lower abdominal wall which significantly slows the missile’s velocity. If a bullet has enough energy to enter the uterus, it is likely to rest there.

Approximately 19 percent of women who sustain gunshot wounds to the uterus also have associated injuries to other abdominal organs. In addition, approximately 60 percent of gunshot wounds to the gravid uterus cause some degree of fetal injury. In addition to direct fetal trauma, injury to the placenta, membranes, or umbilical cord further increases the risk of fetal injury or death.

Stab wounds are similar to gunshot wounds, but typically have less energy associated with them. Knife wounds are less common than bullet wounds and the patient’s prognosis is usually better. In one study, only 1.4 percent of 1,180 stab wounds resulted in maternal death. As with firearm injuries, organ injury from stab wounds is directly related to organ size.

Pre-hospital care of the pregnant victim of penetrating trauma is essentially the same as for non-pregnant patients. Emergency workers should always keep in mind, however, that with a pregnant patient they are dealing with two lives instead of one.

Non-penetrating (blunt) trauma
Falls and motor vehicle accidents are the most common cause of non-penetrating trauma. As the pregnant uterus enlarges, the patient’s weight distribution is altered. The front of the abdomen becomes heavier, and normal curvature of the lumbar spine is exaggerated. This alters the patient’s gait, making falls more likely than in the non-pregnant state. Falls which result in a fracture of the pelvis show increased incidence of placental separation as well as more fetal skull and long bone fractures.

Although motor-vehicle accidents are a common cause of injury in general, fewer than one percent of pregnant patients in motor vehicle accidents sustain injury. Despite rumors to the contrary, use of the lap belt with the shoulder belt has not shown an increase in uterine injury. The likelihood of injury is directly related to vehicle damage. The greater the vehicle damage, the greater the likelihood of serious injury. EMS personnel should always consider the severity of the accident and develop an appropriate index of suspicion for patient injury. Index of suspicion is the anticipation of the nature and severity of the patient’s injuries based on analysis of the scene and the mechanism of injury. For example, a patient struck by a motor vehicle traveling 40 mph is likely to sustain more serious injuries than if the vehicle were traveling 10 mph.

The most common cause of maternal death in motor vehicle accidents is head injury. The most common cause of fetal death is maternal death. Fetal death with maternal survival is typically due to placental separation. Serious motor vehicle related injuries in the pregnant patient can cause placental separation and retroperitoneal hemorrhage (bleeding in the space behind the peritoneum). Pre-hospital personnel should always consider these complications in traumatized patients who are pregnant.

Assessment and care for the pregnant trauma patient
Assessment and care of the pregnant trauma patient is essentially the same as for non-pregnant victims. However, special consideration should be paid to anatomical and physiological changes associated with pregnancy [see sidebar], as well as subtle signs and symptoms which may indicate serious injury. Remember that the vital signs of the pregnant patient are usually different from those who are not pregnant. Important points to remember include:

• Resting pulse rate is usually 10-15 beats per minute faster than in the non-pregnant state. Blood pressure is usually 10-15 mmHg lower than in the non-pregnant state. Thus, don’t mistake the normal vital signs of a pregnant patient as signs of shock!
• Blood loss of 30-35 percent of the total blood volume can occur before there is a significant change in a pregnant woman’s blood pressure

Two physical findings have been found to be highly associated with pregnancy-related complications such as premature labor, placental separation, fetal injury, and fetal death. These are uterine tenderness and vaginal bleeding. Note: Lack of either of these findings does not exclude serious, life-threatening injury. Uterine tenderness typically is detected by gentle palpation of the abdominal wall over the uterus (or the patient may complain of abdominal pain around the uterus without palpation). Vaginal bleeding may be copious or scant, depending on the degree and location of placental separation. Visual inspection of the vulva determines the presence of vaginal bleeding. Internal examination of the vagina should never occur in the field.  

Pre-hospital care for the pregnant trauma patient is very similar to that of the non-pregnant patient:

1. Complete the primary assessment:
• Secure the airway and stabilize the cervical spine
• Assess breathing
• Assess circulation
• Control severe hemorrhage
2. Manually immobilize the cervical spine
3. Determine the transport decision. Load and transport critical patients immediately. Stable patients should undergo further assessment
4. Administer oxygen at 100 percent using a non-rebreather mask (Administration of oxygen to the mother increases oxygen delivery to the fetus)
5. Perform the secondary assessment. Pay particular attention to:
• Uterine tenderness
• Vaginal bleeding
6. If possible (especially for lengthy transports), assess and monitor fetal heart rate en route
7. Start an intravenous line of lactated Ringer’s solution if possible. Consider the possibility of shock and, if needed, start two lines with large bore (14-16 gauge) catheters.
8. Consider application of the pneumatic anti-shock (PASG) trousers if shock is apparent or if there is significant lower extremity or pelvis injuries. Do not inflate the abdominal compartment
9. Monitor the EKG. If pulse oximetry is available it too should be applied
10. Transport to appropriate facility

Remember that the fetus’ life depends on the life of the mother. When caring for the pregnant trauma patient you are, in essence, caring for two patients.

References

•  Lee in Campbell : Basic Trauma Life Support . 2nd ed. 1988, Englewood Cliffs, NJ: Brady/Prentice-Hall.

•  Pearlman, Tintinalli, and Lorenz: "A prospective controlled study of outcome after trauma in pregnancy" American Journal of Obstetrics and Gynecology. 162(6):1502-04. June 1990

•  Goodwin and Breen: "Pregnancy outcome and fetomaternal hemorrhage after noncatastrophic trauma" American Journal of Obstetrics and Gynecology. 162(3):665-71. March, 1990

•  Bledsoe, Porter, and Shade: Paramedic Emergency Care . Brady/Prentice-Hall, Englewood Cliffs, NJ, 1991

•  Pimental L: "Mother and Child. Trauma in Pregnancy" Emergency Medicine Clinics of North America . 9(3)L549-63. August 1991

•  Committee on Trauma, American College of Surgeons: Advanced Trauma Life Support . American College of Surgeons, Chicago , IL 1989