What is the recommended emergency management of a pregnant trauma patient, including maternal stabilization, fetal monitoring, imaging with shielding, Rh immunoglobulin administration, and criteria for emergent delivery?

Emergency Management of Trauma in Pregnancy

Maternal stabilization is the absolute priority in pregnant trauma patients, as optimal resuscitation of the mother is the best early treatment of the fetus. 1, 2

Initial Assessment and Resuscitation

Primary Survey - Maternal Focus First

• Every female of reproductive age with significant injuries should be considered pregnant until proven otherwise by definitive pregnancy test or ultrasound. 1
• The primary survey focuses entirely on maternal stabilization before fetal assessment, as maternal compensation may occur at fetal expense. 1, 3
• Establish two large-bore (14-16 gauge) IV lines immediately for aggressive fluid resuscitation. 1

Airway Management

• Insert a nasogastric tube in semiconscious or unconscious pregnant trauma patients to prevent aspiration of acidic gastric content, as pregnancy increases aspiration risk. 1
• Consider early intubation if respiratory compromise develops, as progesterone-mediated hyperventilation means normal PaCO2 may indicate impending respiratory failure. 4

Breathing and Oxygenation

• Administer supplemental oxygen to maintain maternal oxygen saturation >95% to ensure adequate fetal oxygenation. 1
• If thoracostomy tube placement is needed, insert it 1-2 intercostal spaces higher than usual due to diaphragmatic elevation in pregnancy. 1

Circulation and Positioning

After mid-pregnancy (≥20 weeks gestational age when uterus is palpable at or above umbilicus), manually displace the gravid uterus to the left using continuous two-handed traction to relieve aortocaval compression. 5, 1

• Do NOT place the patient in left lateral tilt position during resuscitation, as this reduces cardiac massage efficacy to only 10% of normal cardiac output. 5
• Maintain supine position with manual leftward uterine displacement by a designated team member throughout resuscitation. 5
• Use vasopressors only for intractable hypotension unresponsive to fluid resuscitation, as they adversely affect uteroplacental perfusion. 1
• Transfuse O-negative blood in Rh-negative mothers until cross-matched blood is available to prevent Rh alloimmunization. 1

Imaging and Diagnostic Studies

Radiographic Imaging

Do not defer or delay radiographic studies including abdominal CT when indicated for maternal evaluation due to concerns about fetal radiation exposure. 5, 1

• Fetal radiation exposure >100 mGy carries risk of mental retardation (0.025 IQ points lost per mGy above 100 mGy), but exposure >50 mGy doubles childhood cancer risk. 5
• Thresholds of 200-500 mGy may warrant consideration of pregnancy termination, but typical diagnostic imaging falls well below these levels. 5
• The risk-benefit balance should favor maternal diagnostic needs, as maternal stabilization is paramount. 5

Ultrasound Evaluation

• Perform FAST (Focused Assessment with Sonography for Trauma) scan as a bedside triage tool, though it has lower sensitivity for detecting traumatic abdominal injury in pregnant versus non-pregnant patients. 5
• FAST is specific for ruling in intraabdominal hemorrhage but not sufficiently sensitive to exclude it. 5, 4
• Pelvic ultrasound can assess uterine integrity, amniotic fluid level, fetal viability, and retroplacental hemorrhage, though sensitivity for placental abruption is only 40-50%. 5

Laboratory Tests

• Obtain routine trauma labs plus coagulation panel including fibrinogen level. 1
• Perform Kleihauer-Betke testing in Rh-negative patients to quantify maternal-fetal hemorrhage and determine additional anti-D immunoglobulin dosing needs. 1, 2

Fetal Monitoring and Assessment

Timing of Fetal Evaluation

Fetal assessment should be performed at the end of the primary survey after rapid maternal evaluation, but only after maternal stabilization is underway. 2

• In major trauma, maternal assessment, stabilization, and care are the first priority; fetal heart rate auscultation and monitoring are initiated after maternal stabilization if the fetus is viable (≥23 weeks). 1

Duration of Monitoring

All pregnant trauma patients with viable pregnancies (≥23 weeks) should undergo continuous electronic fetal monitoring for at least 4-6 hours. 5, 1, 2

• Patients with high-risk features require 24-hour observation: uterine tenderness, significant abdominal pain, vaginal bleeding, sustained contractions (>1 per 10 minutes), ruptured membranes, abnormal fetal heart rate pattern, high-risk mechanism of injury, or fibrinogen <200 mg/dL. 5, 1
• Even minor trauma carries moderately heightened risk of premature birth (OR 2.07), cesarean section (OR 2.18), fetal distress (OR 1.84), and fetal death (OR 4.67). 5

Obstetrical Ultrasound

• Perform urgent obstetrical ultrasound when gestational age is undetermined and delivery may be needed. 1
• All pregnant trauma patients admitted for monitoring >4 hours should have obstetrical ultrasound prior to discharge. 1

Rh Immunoglobulin Administration

Administer anti-D immunoglobulin to ALL Rh-negative pregnant trauma patients regardless of injury severity. 1, 2

• Perform Kleihauer-Betke testing to quantify maternal-fetal hemorrhage and determine if additional doses beyond the standard 300 mcg are needed. 1, 2
• This must be done even after minor trauma, as occult fetomaternal hemorrhage can occur. 1

Criteria for Emergent Delivery

Perimortem Cesarean Section

In maternal cardiac arrest with viable pregnancy (≥23 weeks), perform cesarean section no later than 4 minutes after arrest onset to aid maternal resuscitation and fetal salvage. 5, 1, 2

• The objective is fetal extraction within 5 minutes of resuscitation onset. 5
• No maternal survival has been reported after 15 minutes of resuscitation; no fetal survival after 30 minutes. 5
• Do not transport to operating room—perform at bedside even under rudimentary aseptic conditions. 5
• Continue manual leftward uterine displacement during CPR until delivery occurs. 5

Obstetrical Emergencies Requiring Delivery

• Placental abruption: Do not delay management pending ultrasound confirmation, as ultrasound is not sensitive for this diagnosis; DIC accompanies >80% of severe cases. 1
• Uterine rupture: The gravid uterus is at increased risk from blunt trauma; this is a life-threatening emergency requiring immediate delivery. 5
• Maternal instability: In life-threatening maternal complications, immediate delivery should be considered primarily to improve maternal outcomes. 5

Transfer Criteria

Triage Decision Algorithm

Transfer to maternity facility (labor and delivery unit) when:

• Injuries are neither life- nor limb-threatening AND
• Fetus is viable (≥23 weeks) 1

Transfer to trauma unit/emergency room when:

• Major injuries present, regardless of gestational age 1
• Fetus is <23 weeks gestational age 1
• Severity of injury or gestational age is uncertain 1

Timing Considerations

• Do not delay transfer waiting for complete maternal stabilization if the patient is transportable—antenatal transfer improves neonatal outcomes compared to postnatal transport. 6
• Do not delay transport due to inability to continuously monitor the fetus during transfer—maternal stabilization is the priority. 6, 7
• If delivery is imminent, it may be safer to postpone transfer until after childbirth, requiring immediate consultation with the receiving facility. 6

Common Pitfalls to Avoid

• Never perform digital or speculum vaginal examination in cases of vaginal bleeding at ≥23 weeks until placenta previa is excluded by ultrasound. 1
• Do not inflate the abdominal portion of military anti-shock trousers on pregnant patients, as this reduces placental perfusion. 1
• Do not focus on the fetus before the mother is properly stabilized—an apparently stable mother may be compensating at fetal expense. 3
• Do not assume normal maternal vital signs exclude fetal compromise—fetal distress can occur before maternal deterioration. 7
• Do not delay necessary imaging due to radiation concerns—the benefit to maternal diagnosis outweighs theoretical fetal risks in trauma settings. 5, 1