© Springer International Publishing AG 2018Peter Bogach Greenspan (ed.)The Diagnosis and Management of the Acute Abdomen in Pregnancy doi.org/10.1007/978-3-319-62283-5_10
10. Trauma During Pregnancy
Department of Surgery, University of Missouri Kansas City School of Medicine, Truman Medical Centers, Kansas City, MO, USA
Department of Surgery, University of Missouri Kansas City School of Medicine, Kansas City, MO, USA
Stanley M. Augustin
Trauma in pregnant women presents a unique problem. The addition of a second patient adds a layer of complexity to management. Trauma is a significant cause of morbidity and mortality to both the mother and fetus . Trauma represents the leading cause of death in women under the age of 35 . Six to seven percent of pregnancies are complicated by trauma . Common causes include motor vehicle collisions, falls, and assaults. Trauma is a leading cause of death during pregnancy and is related to 50% of maternal deaths . The fetal death rate has been reported at 6.5 per 1000 live births . The primary cause of fetal death is maternal death.
Trauma represents a significant burden to the pregnant patient and fetus. This chapter will explore relevant anatomical and physiological changes, injury prevention, injury patterns, initial and operative management, specific obstetrical complications, and outcomes.
In general, the initial management of pregnant trauma patients mirrors the management of nonpregnant trauma patients. The relevant differences and important distinctions in the pregnant patient will be highlighted.
Anatomy and Physiology of Pregnancy
A complete discussion of the physiological changes in pregnancy is discussed elsewhere. The relevant factors to the trauma patient are discussed here. The pregnant patient can be expected to have increased minute ventilation. A study of the blood gases will reflect the changes in ventilation. The pregnant trauma patient may have an elevated diaphragm. Chest tube placement may need to be 1 to 2 intercostal spaces higher in the pregnant patient. A decrease in lower esophageal sphincter pressure increases the risk of aspiration. Early placement of a nasal or oral gastric tube should be considered in those gravid patients who are without a protected airway.
Cardiovascular vital signs are altered in the pregnant population. An increased heart rate and altered blood pressures are considered to be normal physiological alterations in gravid women. The blood pressure decreases in the first trimester and reaches a low point in the second trimester. It returns to near normal in the third trimester. However, attributing tachycardia and hypotension to normal physiology represents a potential pitfall in the pregnant trauma patient. Plasma volume expands and results in a relative anemia (RBC mass increases by a lesser value). Plasma expansion increases the loss of blood volume necessary to cause clinical hypotension. A relatively “minor” blood loss results in shunting blood away from the placenta. Thus, the fetus may be experiencing shock in a mother with normal or near normal vital signs . The gravid uterus exerts pressure on the inferior vena cava and decreases preload which can result in hypotension when supine.
Trauma represents a serious cause of morbidity and mortality in pregnancy. Simple interventions, however, can protect both the mother and fetus. The utilization of a seat belt is paramount in the pregnant patient. Correct placement and usage of both the lap belt and the shoulder harness provide the best protection. The lap belt should be placed under the abdomen and across the upper thigh. The shoulder harness is placed between the woman’s breasts. Placing the lap belt across the abdomen may result in injury to the uterus and fetus during motor vehicle collision. Nonuse of the shoulder harness exposes the uterus to flexion/compression injuries and increases risk of maternal injury. The greatest benefit of a seat belt is not being ejected from the vehicle.
Domestic violence represents another source of trauma in the pregnant patient. The incidence of domestic violence varies by study and may be as high as 30% . The primary care physician, obstetrician, and trauma team have a duty to identify and recognize warning signs (inconsistent injury/history, frequent hospital/ED/office visits, substance abuse, depression, partner unwilling to leave during examination). Involvement of the appropriate agencies, interventions, and counseling provides safety to mother and fetus . In addition, substance abuse represents an increased risk of trauma along with the additional negative side effects on the fetus. Screening and intervention of at- risk individuals provide another opportunity to intervene before a trauma occurs.
Pregnancy changes the patterns of injury in trauma. However, it does not affect the morbidity or mortality. The changes in injury patterns include more severe abdominal injuries, higher percentage of extremity injuries, and less severe head injuries . Depending on the size of the uterus, the fetus may be more likely to be injured than the mother. The incidence of trauma and the likelihood of injury to the fetus increases with an increase in gestational age . Half of all traumas in the pregnant population occur in the third trimester .
The most common cause of injury is blunt trauma as a result of motor vehicle collisions, falls, assaults, automobile striking pedestrians, and domestic violence.
Trauma patients frequently require multiple imaging modalities . Exposure of the fetus to ionizing radiation represents an obvious concern. However, the risk of ionizing radiation should not outweigh the benefits of imaging in pregnant trauma patients. The imaging necessary to identify injury and treat the mother is obtained. The threat of a missed or misdiagnosed injury represents great harm to the mother and fetus. Despite the concern about ionizing radiation, routine imaging in pregnant trauma patients presents a low risk to the fetus. The typical dose of ionizing radiation to the fetus in a CT study of the abdomen and pelvis is 25 mGy . The dose may be lower with modern CT scanning and the use of automated exposure control . “In 1977, the National Council of Radiation Protection and Measurement issued the following policy statement with regard to radiation and pregnancy: ‘The risk [of abnormality] is considered to be negligible at 50 mGy or less…’” . The American College of Obstetricians and Gynecologists offered a similar statement in 2004: “Women should be counseled that x-ray exposure from a single diagnostic procedure does not result in harmful fetal effects. Specifically, exposure to less than 5 rad [50 mGy] has not been associated with an increase in fetal anomalies or pregnancy loss” . Routine trauma imaging does not appear to increase the risk of radiation-induced diseases. However, it is prudent to limit exposure without compromising patient care. Shielding the uterus is appropriate, when possible, and limitation of the number of nonessential radiographic studies is advisable.