AUTHOR AND EDITOR INFORMATION

Section 1 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

INTRODUCTION

Section 2 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Background

The pregnant trauma patient presents a unique challenge to emergency physicians because care must be provided for two patients—the mother and the fetus. Anatomic and physiologic changes in pregnancy can mask or mimic injury, making diagnosis of trauma-related problems difficult. Care of pregnant trauma patients with severe injuries often requires a multidisciplinary approach involving an emergency physician, trauma surgeon, obstetrician, and neonatologist.

Pathophysiology

To evaluate the pregnant patient, the emergency physician must understand the various physiologic changes that occur during pregnancy. Because balance and coordination are most adversely affected during the third trimester, the frequency of accidental injury is greatest during this period. Although the pregnant patient's blood pressure decreases during pregnancy, changes may not be as great as traditionally thought. Systolic blood pressure changes by only 2-4 mm Hg, while diastolic pressure decreases by 5-15 mm Hg. In addition, the resting heart rate usually increases by only 10-15 beats per minute. Thus, tachycardia or hypotension in pregnant trauma patient should not be attributed solely to the gravid state.

Physiologic anemia in pregnancy is due to a dilutional effect of plasma volume increasing by 50% but red blood cell volume increasing by only 18-30%. Thus, the average hematocrit level is 32-34% and is at its nadir around the 30th to 34th week of gestation. Because the average estimated blood loss is approximately 500 mL for a vaginal delivery and 1000 mL for a cesarean delivery, no change in hemodynamic parameters occurs because of these preemptive adaptations. The uterus, which grows from 70-1000 g, enlarges into the peritoneal cavity after the 12th week of pregnancy. Although it now becomes more susceptible to injury, it also provides protection for other maternal abdominal organs such as the small bowel. The bladder is also moved into the abdomen by the uterus, and the ureters become dilated. Gastrointestinal tract motility decreases.

Frequency

United States

Six to seven percent of all pregnant women experience some sort of trauma, with the greatest frequency in the last trimester. Approximately 0.3-0.4% of pregnant women have traumatic injuries that require hospitalization.

Mortality/Morbidity

The most common cause of fetal death is maternal shock, which is associated with a fetal mortality rate of 80%. This explains why efforts to assess fetal well-being are secondary to resuscitation of the mother. Placental abruption is the second most common cause of fetal death, with fetal mortality rates as high as 30-68%. When maternal death occurs, it usually results from head injury.

• Motor vehicle accidents account for 60-67% of all major injuries. Falls and physical abuse account for most of the rest (10-31%).
• Placental abruption occurs when shearing forces lead to a separation of the rigid placenta from the elastic uterus. Up to 30-50% of patients with major traumatic injuries and as many as 5% of patients with minor injuries have placental abruption after trauma.
• Penetrating wounds injure the fetus in as many as 70% of cases and cause maternal visceral injuries in 19% of cases.

Age

In one trauma center that treats more than 2,500 trauma patients per year, the mean age of pregnant trauma patients was 25 years, with a range of 14-45 years.

CLINICAL

Section 3 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

History

Features of the patient's history may include the following:

• Mechanism
• • Direct abdominal trauma
  • Weapons
  • Seatbelt use, proper or improper. (The American College of Obstetrics and Gynecology endorses the use of a 3-point safety restraint, with the lap belt over the hips, not the uterine dome.)
• Last menstrual period (LMP) and estimated date of confinement (EDC)
• Uterine contractions
• Fetal movement
• Premature rupture of membranes
• Vaginal bleeding
• History of depression, substance abuse, or several ED visits (These factors may suggest domestic violence, which is not dependent on age, race, marital status, or socioeconomic class.) A review of 13 studies found the prevalence of domestic violence to range from 0.5-20.1%.

Physical

• Abdominal examination
• • Inspect for ecchymoses, especially across the lower abdomen, which may indicate a possible seatbelt injury.
  • Palpate for uterine contractions or tenderness. Gestational age can be estimated by the size of the gravid uterus. In general, when the fundal height reaches the umbilicus, gestational age can be estimated at 20 weeks. Once above the umbilicus, the fundal height in centimeters measured from the symphysis pubis correlates well with gestational age.
  • Fetal heart tones can be assessed with Doppler examination or ultrasonography.
  • Note that the abdominal examination is relatively unreliable because peritoneal stretching in the third trimester decreases the density of afferent pain fibers, thereby muting peritoneal signs.
• Sterile speculum examination before bimanual examination
• • Perform these in the absence of vaginal bleeding.
  • Test the fluid for pH and ferning. A pH of 7 indicates amniotic fluid. Vaginal secretions are more acidic, with a pH around 5.
  • Examine for vaginal lacerations, which may signify an open pelvic fracture.
  • Look for bone fragments in the vagina, which signify an open pelvic fracture.
• Bimanual examination
• • In general, the obstetrician should perform this examination.
  • It should be performed in a setting where emergency cesarean delivery can be performed.
• Evaluation for possible domestic violence
• • Ecchymoses of breasts, abdomen, and upper extremities may be present.
  • Injuries at more than one site in varying stages of healing may be observed.

Causes

Causes of traumatic injuries in pregnancy are similar to those in the general population; blunt-injury trauma is the most common cause. Motor vehicle accidents are the leading cause of trauma during pregnancy, followed by falls and direct assaults to the abdomen. Other causes include the following:

• Penetrating trauma
• Domestic violence
• Accidental injury (may be related to physiologic changes that result in loss of balance)

DIFFERENTIALS

Section 4 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

WORKUP

Section 5 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Lab Studies

• Determination of CBC: Pregnancy-induced leukocytosis peaks to levels of 12,000-18,000 per cubic millimeter during the third trimester. During labor, levels as high as 25,000 per cubic millimeter may occur.
• Determination of electrolyte and glucose levels
• Blood typing and cross matching
• Rhesus (Rh) blood group determination (administer RhoGAM if the mother is Rh negative)
• Urine pregnancy testing, if the status is unknown in female of reproductive age with trauma
• Urinalysis
• Assessment of coagulation profile (Most coagulation factors rise throughout pregnancy, although laboratory values remain unchanged except for fibrinogen levels, which nearly double in value.)
• Kleihauer-Betke testing
• • This test is used to detect fetal-to-maternal hemorrhage. In the event of fetal distress, a positive test may indicate life-threatening hemorrhage in the fetal circulation. In addition, the test is useful in Rh-negative mothers because the standard dose of RhoGAM (300 mcg) covers only up to 15 mL of fetal red cells. In major trauma, additional fetal red cells may come into contact with maternal blood, and the Kleihauer-Betke test helps the physician to determine how much additional RhoGAM to administer.
  • Acid elution eliminates adult hemoglobin. Fetal hemoglobin is resistant and stains.
  • This test is usually only indicated for the pregnant patient with major trauma and should not be a routine test performed in the ED.
• Toxicology screening
• D-dimer testing helps in determining the course of action for placental abruption.

Imaging Studies

• Radiologic examinations must be interpreted in the context of pregnancy-related changes. For example, increased AP diameters, mild pulmonary vascular cephalization, cardiomegaly, and a slightly widened mediastinum are seen in normal pregnancy. Similarly, pelvic radiographs show normal widening of the sacroiliac joints and symphysis pubis.
• Radiologic examinations should not be deferred because of the presence of the fetus. Data about injury to the fetus secondary to diagnostic radiology are only suggestive. The 3 primary concerns are the following: radiation-induced cancer, loss of viability, and radiation-induced malformation (small head size). Usually, adverse effects are not expected until the dose is in the 50-100 mGy range (mGy = 0.1 rad). The acquisition of an anteroposterior pelvic radiograph delivers a 0.16-mGy dose to the fetus, while typical dose from CT scanning of the pelvis is approximately 20-50 mGy.
• • Radiation-induced cancer: Data about radiation-induced cancer after in utero exposure suggest that risks for radiation-induced cancer fatality, in children younger than 14 years, may be on the order of 1 in 15,000 children. These results occur when each fetus is exposed to 1.0 mGy of radiation in utero during second or third trimester. The risk ratio for a 50-mGy exposure is about 1:300. Risk of first-trimester exposure may be higher, but the data are less specific.
  • Loss of viability of the fetus: This result is possible if radiation exposure occurs within 2 weeks of conception. For most diagnostic abdominal examinations, this risk probably is less than 1%. All risk estimates related to this possibility at diagnostic dose levels are derived from animal data. The data suggest that, during this period, no increased risk of malformation exists.
• Malformation (small head size): Findings from animal studies suggest a threshold of about 100 mGy, with the most vulnerable period during embryonic development (2-8 wk after conception). Data collected from those affected by the bombings of Hiroshima and Nagasaki suggest that head size may be slightly reduced as a result of exposure to radiation (<200 mGy). However, reduction in intelligence did not occur when exposure occurred during the 2nd-8th weeks after conception. A tendency toward induced intellectual deficit from the 8th-15th weeks after conception was observed (during this period, the brain undergoes rapid neuron development and migration); however, the data are uncertain.
• As a general rule, abdominal CT should be avoided in early pregnancy because other diagnostic modalities, such as ultrasound and diagnostic peritoneal lavage, are acceptable alternatives. CT does, however, allow for better visualization of retroperitoneal and intrauterine injuries. Head and chest CT may be used when indicated because the amount of radiation is much less and because few, if any, alternative diagnostic modalities exist.
• Ultrasonography
• • Use this as a noninvasive diagnostic peritoneal lavage procedure; it is safe for the fetus and does not require transport of the mother out of the ED.
  • Assess fetal viability.
  • Assess for multiple gestations.
  • Assess the size, gestational age, and position of the fetus.
  • Ultrasonography can depict free intraperitoneal fluid or hemorrhage in the mother. The focused assessment with sonography for trauma (FAST) examination has become routine in many trauma centers and has been shown to have high sensitivity and accuracy in the hands of emergency physicians and trauma surgeons.
• MRI: No reports of adverse effects (but few data) exist.
• Ventilation-perfusion (V/Q) scanning: No reports of adverse effects (but few data) exist.

Other Tests

• Cardiotocographic monitoring
• • Monitoring begins at 20-24 weeks of gestational age
  • Fetal distress may be the first sign of maternal hemodynamic compromise because the mother will maintain her vital signs by shunting blood away from the relatively low-resistance uterus.
  • A minimum of 4 hours of monitoring is suggested, even after minor abdominal or flank trauma, to identify patients that might experience placental abruption. This is because clinical signs and symptoms or abruption, such as vaginal bleeding, abdominal pain and tenderness, and uterine tenderness, are often absent.
  • Monitoring for 24 hours is suggested with major trauma or signs of obstetric decompensation, such as persistent uterine contractions, vaginal bleeding, premature rupture of the membranes, or fetal heart rate tracing that causes concern.
  • Ultrasonography has less than 50% sensitivity in diagnosing placental abruption because the density of a fresh clot of blood behind the placenta is the same as the placenta itself.
• Electrocardiography (ECG)
• • The ECG may change as the diaphragm elevates.
  • It may show a left-axis deviation with flattened T waves and, possibly, a Q wave in leads III and aVF.
  • Do not mistake these changes for the ischemic or traumatic changes in blunt chest trauma.

Procedures

• Diagnostic peritoneal lavage (DPL): This study is rarely used nowadays with the advent of ultrasonography. It may be indicated in the pregnant patient where avoidance of radiation exposure through the use of CT is desired and in whom ultrasonography is either unavailable or equivocal. DPLS is safe if performed above the umbilicus with an open technique (lower risk of complications such as inadvertent uterine and fetal injury).
• Perimortem cesarean delivery
• • Perform this within 4 minutes of cardiac arrest to support neurologic function of the fetus.
  • The key to rapid delivery is the use of large of incisions.
  • Perform a midline vertical incision from the xiphoid to the pubis through all layers of the abdominal wall. If the placenta is in an anterior position, cut through it and address the bleeding only after the fetus is delivered.
  • Perform a midline vertical incision through the upper uterine segment.
  • Then remove the neonate, perform suctioning, clamp and cut the cord, and resuscitate the neonate.
  • Continue resuscitation of the mother.

TREATMENT

Section 6 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Prehospital Care

As in any trauma patient, the ABCs of trauma resuscitation must be followed in treating the pregnant patient. The mother should always receive supplemental oxygen. Several additional issues must be considered in treating the trauma patient who is pregnant.

• For patients beyond the 20th week of gestation, the patient should be tilted 15° to the left by placing rolled towels beneath the spinal board. This is done to prevent supine hypotension syndrome, which occurs when the gravid uterus compresses the inferior vena cava. Such compression can decrease cardiac output by up to 30%, which then may cause significant hypotension.
• If warranted, fetal heart tones may be auscultated as part of the initial fetal assessment and to reassure the mother.
• Military antishock trousers (MAST) are considered a class III intervention (inappropriate, possibly harmful) for gravid patients. If they are used, inflate only the leg compartments.

Emergency Department Care

Patients who have minor trauma and who are at less than 20 weeks gestation do not require specific intervention or monitoring. All pregnant women beyond 20 weeks' gestation who have direct or indirect abdominal trauma should undergo at least 4 hours of cardiotocographic monitoring. Resuscitation of the more serious trauma patient must focus on the mother because the most common cause of fetal death is maternal shock or death. It is important to remember that the mother will maintain her vital signs at the expense of the fetus. Because plasma volume is increased 50% and the mother is able to shunt blood away from the uterus, maternal shock may not manifest itself until maternal blood loss exceeds 30%. During the initial ABC assessment, the fetus is addressed only during evaluation of circulation.

If patient is more than 24 weeks' pregnant, the patient should be tilted 15° to the left. Alternatively, one person may be designated to manually displace the uterus to the left. If the patient does not require spinal immobilization, then she can be asked to assume the left lateral decubitus position.

• Airway and breathing
• • All pregnant trauma patients should receive supplemental oxygen, because the fetus is extremely sensitive to hypoxia and because the oxygen reserve is significantly diminished in the pregnant patient.
  • In general, pregnancy does not affect the decision to intubate, although the risk of aspiration is increased (decreased gastric tone, delayed gastric emptying, and cephalad displacement of intraabdominal organs). The use of medications for rapid-sequence intubation in pregnancy is not well studied; however, no absolute contraindications exist.
  • If a chest tube is placed, enter the chest 1 or 2 interspaces higher than usual, because the diaphragm is elevated during pregnancy.
• Circulation
• • Resuscitate the patient with warmed crystalloid administered through large-bore catheters placed for intravenous lines, because as the relative hypervolemia of pregnancy allows for a 30-35% loss of blood volume before hypotension develops.
  • Rule out occult sources of bleeding, because maternal blood flow is maintained at the expense of fetal blood flow.
  • If blood is needed on an emergency basis, use Rh-negative blood unless the patient's Rh status is known.
  • Blood pressure returns to prepregnancy levels as the gestational age approaches 40 weeks.
  • Fetal assessment should be performed early as part of the maternal secondary survey.

Consultations

The pregnant patient with serious traumatic injury requires a multidisciplinary team, which includes an obstetrician, trauma surgeon, and a neonatologist.

MEDICATION

Section 7 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

The goal of therapy is to prevent immune response to Rh-negative fetus after trauma.

Drug Category: Immune serum

Suppresses immune response of nonsensitized Rho(D)–negative mothers who are exposed to Rho(D)–positive blood from the fetus, resulting from a fetomaternal hemorrhage, abdominal trauma, amniocentesis, abortion, full-term delivery, or transfusion accident.

FOLLOW-UP

Section 8 of 9  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

Further Inpatient Care

• Admission criteria
• • Abnormal obstetric findings, such as vaginal bleeding
  • Abnormal fetal heart rate tracings (eg, variable decelerations)

Further Outpatient Care

• Discharge criteria include no abnormal obstetric findings and normal fetal heart tracings.
• Instruct the patient to return in the event of decreased fetal activity, vaginal bleeding, uterine contractions and/or cramping, or spontaneous premature rupture of the membranes.

In/Out Patient Meds

• RhoGAM (Rh immunoglobulin G)

Transfer

• Transfer the patient to a level I trauma center with obstetric and neonatal ICUs.

Complications

• Rupture of amniotic membranes can lead to chorioamnionitis, preterm labor, and cord prolapse.
• Retroperitoneal hemorrhage, uterine rupture (diagnosed with maternal hypotension, palpation of fetal part, radiographic findings), and amniotic fluid embolism (may lead to acute respiratory distress syndrome)
• Placental abruption is the most feared complication in cases of trauma.
• • It occurs in 38-66% of major injuries and in 2-4% of minor injuries. It is the most common cause of fetal death when the mother survives the trauma.
  • Placental abruption may be delayed for as long as 24-48 hours after the traumatic incident.
  • Diagnosis is made with 2 of the following 3 criteria:
    • Tense abdomen with uterine hypotonia
    • Maternal hypertension or hypotension
    • Ultrasonographic evidence of abruption
  • Fetal distress is the most reliable indicator of active or impending abruption.
  • Ultrasonography is an insensitive tool and causes more than 50% of abruptions to be missed. Amniocentesis can be used to make the ultimate diagnosis in desperate situations.
  • Abruption can lead to consumptive coagulopathy.
• Uterine rupture is associated with a fetal mortality rate approaching 100%. Maternal mortality of 10% is usually a result of associated injuries.
• Fetal injury is the leading cause of fetal death in cases of maternal death. Direct fetal trauma is rare because of the protection from the uterus and amniotic fluid.

Prognosis

• Penetrating injury has a perinatal mortality rate of 40-70%, although the maternal mortality rate is less than that in the nonpregnant patient because of the protective effects of the large, muscular uterus on the maternal visceral organs.
• In one urban study, violence accounted for 57% of maternal deaths (48% homicides, 9% suicides).
• Investigators in one study reported a 7% maternal mortality rate in serious automobile injuries and a 14% injury rate in surviving mothers.

REFERENCES

Section 9 of 9

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• References

• Bochicchio GV, Haan J, Scalea TM. Surgeon-performed focused assessment with sonography for trauma as an early screening tool for pregnancy after trauma. J Trauma. Jun 2002;52(6):1125-8. [Medline].
• Connolly AM, Katz VL, Bash KL. Trauma and pregnancy. Am J Perinatol. Jul 1997;14(6):331-6. [Medline].
• Crosby WM, Costiloe JP. Safety of lap-belt restraint for pregnant victims of automobile collisions. N Engl J Med. Mar 25 1971;284(12):632-6. [Medline].
• Curet MJ, Schermer CR, Demarest GB. Predictors of outcome in trauma during pregnancy: identification of patients who can be monitored for less than 6 hours. J Trauma. Jul 2000;49(1):18-24; discussion 24-5. [Medline].
• El-Kady D, Gilbert WM, Anderson J. Trauma during pregnancy: an analysis of maternal and fetal outcomes in a large population. Am J Obstet Gynecol. Jun 2004;190(6):1661-8. [Medline].
• Esposito TJ. Trauma during pregnancy. Emerg Med Clin North Am. Feb 1994;12(1):167-99. [Medline].
• Fildes J, Reed L, Jones N. Trauma: the leading cause of maternal death. J Trauma. May 1992;32(5):643-5. [Medline].
• Goldman SM, Wagner LK. Radiologic management of abdominal trauma in pregnancy. AJR Am J Roentgenol. Apr 1996;166(4):763-7. [Medline].
• Mattox KL, Goetzl L. Trauma in pregnancy. Crit Care Med. Oct 2005;33(10 Suppl):S385-9. [Medline].
• Pak LL, Reece EA, Chan L. Is adverse pregnancy outcome predictable after blunt abdominal trauma?. Am J Obstet Gynecol. Nov 1998;179(5):1140-4. [Medline].
• Pearlman MD, Tintinalli JE, Lorenz RP. Blunt trauma during pregnancy. N Engl J Med. Dec 6 1990;323(23):1609-13. [Medline].
• Pearlman MD, Tintinallli JE, Lorenz RP. A prospective controlled study of outcome after trauma during pregnancy. Am J Obstet Gynecol. Jun 1990;162(6):1502-7; discussion 1507-10. [Medline].
• Poole GV, Martin JN Jr, Perry KG Jr. Trauma in pregnancy: the role of interpersonal violence. Am J Obstet Gynecol. Jun 1996;174(6):1873-7; discussion 1877-8. [Medline].
• Shah AJ, Kilcline BA. Trauma in pregnancy. Emerg Med Clin North Am. Aug 2003;21(3):615-29. [Medline].

Article Last Updated: May 10, 2006