Obstetric Trauma

Overview

• Obstetric trauma refers to any trauma sustained by a pregnant person, which can be life-threatening to both the mother and fetus and requires urgent medical attention. Trauma is estimated to complicate approximately 1 in 12 pregnancies, and in the United States, it is the leading non-obstetric cause of maternal death.² Most cases are blunt rather than penetrating trauma. Trauma can occur throughout pregnancy, and no clear difference has been found for maternal and fetal outcomes based on gestational age.³
• Trauma to the pregnant patient increases the incidence of spontaneous abortion, preterm premature rupture of membranes, preterm birth, uterine rupture, cesarean delivery, placental abruption, and stillbirth. As many as 1 in 3 pregnant patients admitted to the hospital for trauma will deliver during the hospitalization. Therefore, pregnant women should be closely monitored to rule out and/or manage these potential complications.
• Motor vehicle collisions (MVCs) are the most common cause of maternal injury during pregnancy, with an incidence rate of 200-300 cases per 100,000 pregnancies.⁴ In a large-population study examining all fatalities in pregnant women in Sweden over a 10-year period, MVCs accounted for 1/3 of all maternal deaths and for three times as many fetal/neonatal deaths.⁵ A major risk factor for adverse outcomes during MVC is improper seat-belt positioning (the lap belt should be low under the abdomen and the shoulder belt between the breasts).
• Following an MVC, pregnant patients are at higher risk for preterm birth and cesarean delivery. Placental abruption can occur in up to 40% of cases in severe MVCs, such as those involving ejection and high speed.³ Forward displacement of the uterus and maternal folding over the abdomen during an MVC can increase intra-abdominal pressure with strain on the uterus, thereby increasing the risk of placental shearing and abruption.² Significant intrauterine injury also increases the risk of disseminated intravascular coagulation (possibly due to placental products entering maternal circulation).³
• Falls are estimated to account for 17-39% of trauma-associated emergency department visits and hospital admissions in pregnant patients.⁶ Pregnant patients are especially susceptible to falls as pregnancy causes joint laxity and changes in the center of gravity. Though there is less robust data regarding outcomes, it is estimated that 1 in 4 pregnant women will fall at least once during pregnancy, with an increased likelihood of a serious fall requiring hospital admission in the third trimester.²
• Domestic violence/intimate partner violence (IPV) is a common cause of obstetric trauma. Incidence varies widely depending on how IPV is defined; overall, it is estimated at approximately 22.4%, comparable to the general population rate. Thus, it is essential that all pregnant women be screened for IPV during all hospital visits.

Management

• Management of obstetric trauma is largely the same as standard management per ATLS guidelines. However, pregnancy entails specific anatomic and physiologic changes that have implications for management (see the OA summary on physiologic changes in pregnancy). Link
• Because of this complexity, a trauma surgeon and obstetrician should be involved early in the evaluation of a pregnant trauma patient. If delivery is likely, particularly preterm, the neonatal resuscitation team should be consulted. If these services are not immediately available, early consultation/transfer to a trauma center with obstetric capabilities should be considered.

Primary Survey

Control of eXsanguinating Hemorrhage

• If there is soft tissue injury present that is causing significant external blood loss, apply direct pressure, pack the wound if necessary and place a tourniquet if hemorrhage is ongoing despite initial control methods (see OA summaries on prehospital trauma management Link and American College of Surgeons Stop the Bleed Campaign Link).

Airway

• Given the increased vascularity and edema in pregnancy, increased aspiration risk, higher body mass index, increased breast tissue, and higher oxygen consumption, pregnant patients are much more likely to have both an anatomical and a physiological difficult airway. This can be particularly challenging if the patient has not had cervical spine clearance.
  • Definitive airway management, with a cuffed endotracheal tube below the vocal cords, is often recommended earlier than with other trauma patients.
  • If a supraglottic airway device is required, a second-generation device is recommended to allow higher ventilatory pressures and minimize the risk of aspiration.
  • Rapid sequence intubation should be used.
  • Video laryngoscopy and/or fiberoptic should be used for intubation.
  • The airway should be managed by the most experienced provider possible or at least available if required.
  • An orogastric (if intubated) or nasogastric tube should be considered to prevent aspiration of gastric contents in a semiconscious/unconscious patient.
  • Limit multiple airway attempts whenever possible.

Breathing

• Pregnancy decreases functional residual capacity (FRC) by 30% and significantly increases oxygen consumption and minute ventilation. The fetus is also sensitive to maternal hypoxia.
  • Recommend liberal oxygen supplementation whilst the patient is being assessed and stabilized, even if peripheral oxygen saturations are above 92%.
  • Head elevation to >30 degrees if/when possible, to improve FRC. If spine is not cleared, reverse Trendelenburg positioning may help as long as the patient remains hemodynamically stable.
  • If thoracostomy tubes need to placed, aim 1-2 spaces higher in patient with gravid uterus due to upward displacement of diaphragm.
  • Normal PCO₂ is significantly lower in the pregnant population (27-32 mmHg) and therefore a “normal” PCO₂ level (35-45 mmHg) may portend imminent respiratory failure.
  • Consider early intubation and ventilation if airway and/or spontaneous ventilation are compromised.

Circulation

• Pregnancy increases total blood volume – plasma blood volume doubles by the end of the third trimester. This may therefore mask the signs of trauma hemorrhage. At term, blood loss of 1.5L or more may occur before signs of hypovolemia are present.
  • Place two large-bore intravenous (IV) access ideally in the upper limbs.
  • Pregnancy causes aortocaval compression once fundal height reaches the umbilicus which decreases cardiac output when supine by 30%. This is typically around the 20th week of gestational age. Perform left uterine displacement either by manual uterine displacement or by tilting the table to the left by 25-30 degrees (Figure 1) to decrease aortocaval compression from gravid uterus (more than 20 weeks gestation).
  • Assess for shock and control hemorrhage.
  • Resuscitate with fluid and blood products to restore/maintain end-organ perfusion.
    • Consider target of mean arterial pressure more than 60-65 mmHg and systolic blood pressure more than 90 mmHg.
    • In hemorrhagic shock, recommend initiating massive transfusion protocol and resuscitation with blood rather than fluid (though fluid can be given as temporizing measure until blood is available).
    • Give whole blood if available, otherwise give 1:1:1 product resuscitation.
    • There is ongoing debate regarding the use of low titer group O whole blood (LTOWB) in women of childbearing potential due to concerns of alloimmunization. LTOWB tends to be O-positive in most centers and thus may contribute to alloimmunization in Rh-negative patients. However, it appears that the overall risk of alloimmunization is low (3-20%) and can be treated whilst the risk of withholding blood resuscitation puts the pregnant woman and fetus at very high risk of morbidity and mortality.⁷ In general, it is essential in suspected hemorrhagic shock to resuscitate with blood product as soon as possible, as this has been shown to improve survival. Rh-negative women who do receive O positive whole blood should be followed up with appropriate dosing of RhD Immunoglobulin (Rhogam).
  • Vasopressors can theoretically decrease placental perfusion. However, once the patient has been adequately fluid resuscitated with volume/blood products, if they remain hypotensive or with signs of hypoperfusion, pressors and / or inotropes should be commenced.
  • Must have high index of suspicion for hemorrhage even if vital signs are normal – recommend early extended Focused Assessment with Sonography in Trauma (eFAST) exam and all other appropriate workup to rule out hemorrhage (see OA summary on ultrasound in trauma Link).
  • Dilutional anemia (10-14 mg/dL) is normal in pregnancy; however, if the patient is anemic on presentation, one should have a high suspicion for trauma hemorrhage.
  • In pregnancy, the liver is hypermetabolic and produces more clotting factors and fibrinogen, and therefore pregnant patients are hypercoagulable and at elevated risk for disseminated intravascular coagulation. At term, the normal fibrinogen level in pregnancy is much higher (360-910mg/dl) than the non-pregnant population (200-400 mg/dL). A fibrinogen level less than 400mg/dl is an independent risk factor for postpartum hemorrhage. Therefore, higher levels of fibrinogen should be targeted during blood product resuscitation (300-400 mg/dL).
  • Pregnant patients can have worsened bleeding from pelvic fractures given higher uterine and pelvic blood flow: must have high suspicion for this with high impact injuries and place pelvic binder.
  • Tranexamic acid should be given as per standard trauma guidelines (see OA summary on tranexamic acid in trauma Link).
  • In case of maternal cardiac arrest or profound hemodynamic instability, resuscitative hysterotomy (previously known as perimortem caesarean delivery) should be performed within 4 minutes as it increases cardiac output by up to 30% and improves maternal and fetal outcome. This may be carried out by the trauma surgeon or the obstetric team. Many hospitals will advocate for a direct transfer to the operating room for patients arresting in the prehospital setting.
  • Vertical incision from pubic symphysis to umbilicus with retraction and then vertical incision on uterus to deliver fetus recommended. Goal of delivery within 5 minutes once procedure is initiated. The standard midline laparotomy approach enables other sources of hemorrhage to be explored once the fetus has been delivered (see OA summary cardiopulmonary resuscitation in pregnancy Link).
  • In general, if there is ongoing post-partum hemorrhage after a resuscitative hysterotomy, uterotonics are not the first line therapy (due to the risk of drug side effects, especially hypotension with oxytocin). Damage control resuscitation and surgical management of bleeding are prioritized.

Disability

• Assess consciousness and rapid neurologic evaluation using Glasgow Coma Scale
• Look for lateralizing signs and pupil reactivity.

Exposure

• Thoroughly examine patient for other injuries
• Given elevated risk of placental abruption and uterine rupture (though rare), thoroughly evaluate for concealed hemorrhage with abdominopelvic exam including assessment for vaginal blood loss.
• Avoid hypothermia to minimize coagulopathy.

Secondary Survey

• Following initial stabilization of the patient, during the secondary survey, an urgent obstetric and fetal assessment should be performed to promptly identify and manage obstetric complications.8 When possible, this should be performed by an obstetric team in conjunction with the trauma team. In addition, the trauma team should continue to perform the remainder of the secondary survey, as in non-pregnant patients, according to ATLS guidelines.
  • Head-to-toe examination to evaluate for additional injuries.
  • Focused obstetric history (CODE)
  • Complications of pregnancy
  • Obstetric history and prenatal clinician
  • Dating method and estimated due dates.
  • Events (e.g. leaking of fluid, bleeding, contractions, fetal movement)
  • Recommend performing an abdominopelvic exam.
  • Concerning findings include vaginal bleeding, rupture of membranes, bulging perineum, and the presence of contractions.
  • In viable pregnancies (≥ 23 weeks), recommend initiation of continuous cardiotocographic monitoring for 4-6 hours and obstetric ultrasound. Extend monitoring to 24 hours if more than 6 contractions per hour.
  • Give Rhogam if a pregnant patient is Rh-negative.
  • Fetal maternal hemorrhage test (Kleihauer Betke or flow cytometry) to evaluate for the presence and quantity of fetal blood in maternal circulation.

Labs/Imaging

• Standard trauma labs should be obtained (complete blood count, comprehensive metabolic panel, lipase, type and screen, activated partial thromboplastin time, prothrombin time and international normalized ratio, venous blood gas with lactate and glucose, and urinalysis, urine toxicology). In addition to these standard labs, obtain a fibrinogen level (See discussion above).
• Early type and crossmatch
• A Focused Assessment with Sonography for Trauma (FAST) exam should be performed.
  • One large study found similar rates of sensitivity and specificity of the FAST exam in pregnancy for the detection of free fluid in blunt abdominal injury (61% sensitivity and 94% specificity in pregnant women vs. 71% sensitivity and 97% specificity in nonpregnant women)⁹
• In general, imaging studies should be performed as clinically indicated, regardless of pregnancy status, particularly in a high-energy mechanism of trauma with concern for maternal injury.
  • According to the American College of Obstetricians and Gynecologists, radiation below 5 rad (50 mGy) is considered to pose little to no risk of teratogenicity or fetal loss, particularly after the first trimester.¹⁰
  • Ultrasound and magnetic resonance imaging (MRI) are not associated with adverse effects to fetus. Gadolinium contrast should be avoided when possible, in pregnant patients undergoing MRIs due to teratogenic effects in animal studies.
  • Trauma imaging, including computed tomography scans, typically falls below the threshold of 5 rads. If numerous studies are required, recommend consulting a radiologist for assistance with dose calculation and/or potential protocol modifications.