Trauma in Pregnancy

Context

True Case1

A 33-week pregnant lady was brought to her local Emergency Department (ED) following a multiple-car motor vehicle collision. According to the paramedics, the damage to the car was minimal on the patient’s side, and the patient was unrestrained. The reported speed was 20 mph. The patient self-extricated and was sat on the pavement on their arrival. She was complaining of left knee pain and irregular abdominal cramps at the scene.

She was evaluated by an emergency physician within 15 minutes of her arrival. All of her observations were within the normal range, point-of-care-ultrasound (POCUS) was negative for free fluid, her knee assessment did not warrant an X-ray, and she was referred onto the Obstetric Assessment Unit (OAU) for further evaluation.

Upon arrival at the Obstetric Assessment Unit, she was in pain. The patient reported that the abdominal cramps became stronger and more frequent while in the ED. She deteriorated further  whilst on the unit and she was rushed to the theatre. She was subsequently found to have a placental abruption.

Facts and Statistics

Trauma in pregnancy, whether minor or major, increases the risk of preterm labour, placental abruption, foeto-maternal haemorrhage, and pregnancy loss. Additionally, delivery after a traumatic event carries significant risk of morbidity and mortality for both the mother and foetus.

In the UK, it can be expected that 1 in 100 women of childbearing age suffering major trauma will be pregnant, although this is likely to be an underestimate because of lack of routine screening for pregnancy on admission to the ED.2 The most common mechanism of injury in these patients is road traffic collision (RTC), followed by falls and assault.2

Road traffic collision:  these account for more than half of all maternal trauma. Intrauterine shear forces and the contrecoup mechanism associated with rapid deceleration can result in placental abruption or uterine rupture in the absence of other obvious injury. Incorrect use or non-use of seatbelts increases the risk of such injuries.2

Falls: Low-height falls are common in pregnancy, particularly during the third trimester, as altered centre of gravity develops. The majority of falls do not result in significant injury although in rare cases, shear forces or direct abdominal trauma may result in obstetric complications.3

Physical assault and self-inflicted violence: Around 8% of females experience some form of domestic abuse.4 Many women are assaulted for the first time during pregnancy and are at an increased risk of progression to being murdered whilst pregnant and postpartum.5  Murder is usually perpetrated by a partner or family member, and is violent in nature (stabbing, strangulation, and blunt head injury).5 The abdomen is most targeted, followed by the genital area, potentially resulting in both maternal and foetal injury. A vague history of mechanism of injury during pregnancy raises suspicion of domestic violence and should prompt referral to the Safeguarding Team according to local protocols. Suicide attempts are more often by violent means during pregnancy. Common mechanisms include hanging, falling from a height and stepping into the path of a vehicle.

Burns: Burns and inhalational injuries are rare in pregnancy but require specialist care.

Definitions

Anti-D (Rh Immunoglobulin): is a blood product used to prevent Rhesus (Rh) sensitisation. It is given to Rh-negative mothers when potential foetal-maternal haemorrhage has occurred, in order to prevent maternal sensitisation to Rh-positive foetal cells. It should be given within 72 hours of trauma, even if the Kleihauer-Betke test is negative. The dose in acute trauma is 500IU given intramuscularly (IM). This is distinct from the routine antenatal anti-D prophylaxis (RAADP), which is 1500IU IM. Advice should be sought from a haematologist, as higher doses may be required.6

Cardiotocography (CTG): is a monitoring tool used in obstetrics to assess foetal well-being, particularly during the third trimester and labour. It records both foetal heart rate (FHR) and uterine contractions.

Eclampsia: is the new onset of generalised tonic-clonic seizures or coma in pregnant or postpartum woman with preeclampsia, in the absence of other neurologic conditions. It can occur antepartum, intrapartum, or within 6 weeks postpartum. It results from severe cerebral vasospasm, oedema, and haemorrhage. It is a life-threatening emergency for both mother and foetus. Treatment requires immediate magnesium sulphate, rapid blood pressure control, and immediate delivery of the baby.

Injury severity score (ISS):  is an anatomical scoring system used to assess the overall severity of trauma in patients with multiple injuries. It helps guide clinical decisions, assess prognosis, and compare outcomes across trauma cases. Ranges from 0 to 75. Calculated by sum of the squares of the highest three Abbreviated Injury Scale (AIS) scores. Interpretation: ISS 9–15: Moderate trauma, ISS 16-24: Severe trauma, ISS ≥ 25: Very severe trauma, high mortality risk.

Major Trauma : The National Institute for Health and Care Excellence (NICE) and the National Clinical Guideline Centre (NCGC) define major trauma as an injury or combination of injuries that are life-threatening and could be life changing because it may result in long-term disability.7

Minor Trauma: any trauma that does not meet a major trauma criterion.

Normal Foetal Heart Rate:  110-160 beats/min

Pregnancy-induced hypertension is blood pressure ≥140/90 mmHg that develops after 20 weeks’ gestation without signs of preeclampsia.

Resuscitative Hysterotomy: Previously known as “perimortem c-section”, this is a bedside procedure performed to resuscitate a woman in middle-to-late pregnancy who is in cardiac arrest, in order to remove the foetus thereby abolishing the aortocaval compression caused by the pregnant uterus.8

Viable foetus: A viable foetus is a foetus that can survive outside the uterus. This depends on multiple factors including gestational age, birth weight and available medical care. In the context of resuscitation, this is generally accepted to be beyond 20 weeks of foetal life (22 weeks of amenorrhea). The fundus is usually palpable above the umbilicus.

The approach to the care of a pregnant patient who has sustained traumatic injuries requires special consideration and understanding of the unique challenges present due to the altered anatomy and physiology. These changes include:

Table 1: Dynamic anatomical and physiological changes of pregnancy 9,10

 

Clinical Assessment

The standard trauma algorithm should be followed when evaluating a pregnant individual who has experienced any trauma. The assessment includes a primary, secondary, and tertiary survey. The primary assessment should follow the <C>AcBCDE approach aiming to identify and immediately correct any life-threatening injury to the mother. 

Attention should be paid to the observations (vital signs) as they change throughout normal pregnancy and through different patient position. Noting the physiological changes when managing an injured pregnant patient is crucial. Continued manual uterine displacement and left lateral tilt will give you the true BP of the patient with a gravid uterus (image 2). The continuous manual uterine displacement is the favourable approach as a left lateral tilt is not always practical with a conventional ED trolley and it can make the chest compressions less effective if required.

Image 2. Continues Manual Uterine Displacement Application and Left Lateral Tilt12 (used with permission)

Continuous manual uterine displacement should be used for any female with a uterus palpable at or above the umbilicus (image 3).

Image 3. Fundal height and gestational age13

Risk Stratification

Your primary assessment should stratify those at greatest risk from any kind of injury. In addition to the six life-threatening injuries learned from ATLS (airway obstruction and laryngotracheal injury, tracheobronchial tree injury, tension pneumothorax, open pneumothorax, massive haemothorax, and cardiac tamponade), you should be looking for the following:

• Subtle signs of penetrating abdominal injuries
• Signs of ruptured gestational membranes
• Bulging perineum
• Presence of contractions
• Abnormal foetal heart rate or rhythm

The assessor should also look for the early signs of possible complications, keeping in their mind that what seems like a minor trauma might escalate very quickly. The most common complications include14,15:

1.Uterine rupture: More common with direct abdominal trauma in second half of pregnancy. Seen in severe RTCs, pelvic fractures and penetrating trauma. Signs and symptoms include:

• Maternal shock
• Abdominal distension
• Abnormal uterine contour
• Abnormal foetal lie (oblique or transverse)
• Palpable foetal parts
• Sudden abnormal FHR pattern
• Ascent of foetal presenting part

2. Placental Abruption: Most common cause of foetal demise in blunt trauma. Ultrasound (US) alone is not sensitive → do not delay treatment for ultrasound if abruption suspected. Signs and symptoms include:

• Abdominal cramps/pain
• Uterine tenderness
• Vaginal bleeding (70%, may be absent if retroplacental)
• Uterine contractions or hypertonicity
• Signs of foetal distress on a toco monitor are often the earliest indicator (decelerations, tachycardia, bradycardia, and loss of variability)

3. Amniotic fluid embolus: The patient may present much like a massive pulmonary thrombotic embolus. There is no specific treatment for this except supportive care, which may include intubation, vasopressors, and transfusion.

4. Preterm labour: Trauma in pregnancy is associated with 2x higher risk of preterm delivery.

Red flags of foetal loss or placental abruption16:

• Maternal heart rate > 110
• Injury Severity Score > 9
• Evidence of placental abruption
• Foetal heart rate > 160 or <120
• Ejection during a motor vehicle crash
• Motorcycle or pedestrian collisions

• FBC, U&Es, LFTs, Coagulation profile (INR, PTT, fibrin degradation, fibrinogen, i-Coombs), Blood grouping and cross matching, Kleihauer-Betke test (Rh-factor type screening).
• POCUS: FAST scan is a “rule-in”, not a “rule-out” assessment. Evidence shows that it is less sensitive in pregnant patients compared to non-pregnant patients due to a mass effect of the enlarging uterus.17 Careful interpretation is needed.
• Radiographic imaging as directed by ATLS assessmentand should not be delayed or deferred due to concern for foetal radiation exposure in the major trauma setting.16
• Tocographic and foetal monitoring (image 4) – VEAL CHOP
  • Variable – Cord compressionEarly – Head compressionAccelerations – Okay
  • Late – Placental insufficiency

Image 4. CTG with examples18 (used with permission)

Prehospital

The prehospital care of the pregnant trauma patient largely mirrors the care provided to the non-pregnant patient. This involves rapid assessment, performance of necessary stabilisation treatments, and transport to the closest appropriate medical facility. Most patients with major trauma will be transferred directly to a major trauma centre (MTC). It is important when you receive the notification (pre-alert) to get a complete ATMIST report (Age; time of incident & expected arrival to hospital; mechanism of injury; injuries seen or suspected; signs and observations; and any treatment given by crew).

It is good practice when receiving any trauma call involving a female patient, to ask about the pregnancy status and gestational age.

Preparations to Receive the Patient

• Assemble your team. Request intensive care, obstetrics and neonatology attendance in addition to your trauma team.
• Alert your haematology lab and blood bank of the imminent arrival of the injured pregnant patient, who will more than likely need blood transfusion/massive blood transfusion.
• Prepare your equipment and drugs, including neonatal resuscitation equipment and having a resuscitative hysterotomy pack on standby if anticipating cardiac arrest.  
• Before arrival, discuss the modifications of care with the team i.e. manual uterine displacement, foetal heart rate assessment, resuscitative hysterotomy and neonatal resuscitation, and assign roles.

Receiving the Patient16

Before taking the handover, rapidly assess airway patency, central pulse, presence or absence of any  catastrophic bleeding and ensure immediate and continuous uterine displacement if the gestational age >20 weeks or fundal height is above the umbilicus.

• Encourage the whole team to listen in with a “hands off, mouth shut” approach.
• In the case of ongoing CPR, transfer the patient onto the hospital trolley, establish BLS, identify the rhythm and begin the first ALS cycle before handover.
• Gather an ATMIST and AMPLE history, along with brief details of gestation on handover.
• If your facility is unable to offer obstetric services, stabilise the patient and arrange for prompt transfer to a facility that does.

Principles of Management

• Assessment and stabilisation of the mother is the priority (concomitant assessment and intervention).
• Analgesia is always required. Inform the obstetrician and neonatologist about doses and times.
• Non-viable foetus (<23-24wks): Standard treatment of trauma as no obstetric intervention will alter the outcome.
• Viable foetus (>23-24wks): Pregnancy-modified treatment standards, including continuous cardiotocographic (CTG) monitoring is recommended.

The Primary Assessment

Proceed with the primary survey as <C>AcBCDE, keeping in mind the modifications needed (see Table 3). Continuous foetal monitoring is crucial as foetal haemodynamics are more sensitive to maternal decrease in blood flow and oxygenation; thus, foetal distress can be sign of occult maternal distress.

Table 3: Adaptations to the initial management of a pregnant trauma patient10,19

Approach to Pregnant Patients with Burns

Evidence of maternal airway burns requires expeditious intubation before further oedema renders this impossible. Significant burns result in major fluid shifts and insensible losses requiring urgent correction, in order to maintain organ and utero-placental perfusion. Hypoxaemia secondary to smoke and toxin inhalation must be identified and managed urgently to maintain oxygen delivery to mother and foetus.

Remember that the abdomen in late pregnancy represents an increased proportion of total body surface area, which may lead to an underestimation of the percentage burn if abdominal burns are present. All pregnant patients with significant burns, airway burns, or suspected inhalation injury should be transferred to a tertiary burns centre with available obstetric services as soon as feasible. Three maternal burns of more than 40% TBSA indicate a poor foetal and maternal prognosis and increase the strength for early foetal delivery.

Cardiac Arrest and Resuscitative Hysterotomy21,22

Resuscitative hysterotomy is indicated for any maternal cardiac arrest without ROSC within 4 minutes and estimated gestational age >24 weeks based on fundal height estimate.

Equipment Needed

• PPE (including eye protection)
• Scalpel
• Large scissors (Tuffcuts)
• HaemostatsSterile towels/gauze
• Sterile gloves
• Betadine or Chlorhexidine

The Procedure

• Advise the team to continue chest compressions, as per Resuscitation Council UK (RCUK) guidelines, during the procedure.
• Clean the abdomen widely.
• Use a scalpel to make a midline incision from the uterine fundus/xiphisternum to the pubic symphysis.
• Dissect through layers into the peritoneal cavity using scissors.
• Use an assistant to retract the layers of muscles and skin.
• Make a 2cm vertical midline incision into the uterine cavity using the scalpel.
• Insert two fingers into the uterine incision between baby’s body and myometrium, and use scissors to advance the incised opening.
• Reach for the baby’s head.
• Ask an assistant to apply fundal pressure to help deliver baby.
• Manually deliver the baby from the uterus, avoiding grasping the baby around the abdomen.
• Clamp the umbilical cord with the 2 clamps then cut between them and pass infant to neonatal team.
• Deliver the placenta by gentle traction and look at it to make sure it is all intact with no missing pieces.
• Pack the uterus with sterile towels (count the number of towels and ask your scribe to write down the number used).
• External uterine massage to help the uterus contract.
• Continue maternal resuscitation.
• Do not forget to give antibiotics in the event that the mother survives.

Complications

• Foetal injury
• Disseminated intravascular coagulation (DIC)
• Haemorrhagic shock

The Secondary Survey

The secondary survey aims to provide a comprehensive picture of the patient’s condition, ensuring all injuries are identified and managed. Start by repeating the primary survey and checking that all the required interventions have been made, including administration of any medications. Proceed with the secondary survey after stability is achieved. The survey includes examining the patient from head-to-toe, anteriorly and posteriorly, and not excluding any orifice. It should also include a full obstetric assessment including vaginal pH and foetal assessment, which includes monitoring with cardiotocography and ultrasound. Perform any required imaging, including CTs.

By the end of your secondary survey, you should classify your patient into:

• Mother Stable, Foetus Stable (minor injury does not exempt significant foetal injury) – monitor child.
• Mother Stable, Foetus Unstable – if baby remains distressed despite optimising mum, caesarean section should be considered.
• Mother Unstable, Foetus Unstable – focus efforts on rapid restoration of maternal physiology.

Your secondary survey should also include:

• A complete systematic documentation of all identified injuries
• A complete neurological evaluation
• A complete medical history
• Monitoring changes in vital signs
• Identifying the need for additional diagnostic studies.
• Prevention of further injury from missed injury.

Foetal Considerations

It is important to understand that the well-being of the foetus is based on the successful resuscitation of the mother. By managing the mother, you will achieve:

• Maintenance of adequate foeto-uterine perfusion and oxygenation.
• Prevention of hypoxia, hypotension, acidosis and hypothermia.

Foetal Monitoring

The foetal assessment should be started as early as possible from patient arrival to ED and monitoring should be well established before the beginning of the secondary survey:

• Continuous cardiotocographic (CTG) monitoring is needed for:
  • A minimum of 6 hours if abruption is suspected or if the mechanism is concerning, even if not initially identified.26
  • 4-6 hours, if there are no risk factors for foetal loss.
  • 24 hours, if there are risk factors for foetal loss/abruption.
  • The duration of cardiotocographic (CTG) monitoring should be extended to 24 hours if, during the first 4 hours, mum develops > 4 contractions per hour, persistent uterine tenderness, a concerning foetal monitor strip, vaginal bleeding, or rupture of the membranes.

• Frequent uterine activity is more predictive of abruption than ultrasound (US):
  • >8 contractions/hr for 4hrs – high risk for abruption
  • 3-7 contractions/hr for 4hrs – extend monitoring for 24hrs
  • <3 contractions/hr for 4hrs – safe for discharge

Disposition

• Admit any pregnant patients with a minor injury with any of the following:
  • Vaginal bleeding or leakage/suspected leakage of amniotic fluid;
  • Uterine irritability, i.e. patient reports frequent contractions after the injury
  • Evidence of hypovolemia
  • Abdominal tenderness;
  • Changes or absence of foetal heart on CTG.

Care should be provided at a facility with appropriate foetal and maternal monitoring and treatment capabilities. The foetus may be in jeopardy, even with apparently minor maternal injury.

• Discharge only after prompt follow-up with obstetrics and advise the patient to record foetal movement for a week. If they note fewer than four movements in an hour, they should be advised to see an obstetrician immediately.

Debrief

It is good practice to debrief after any resuscitation, but particularly one of this complexity.

Start by checking if everyone is ok. If so, proceed using the STOP mnemonic:

S : Summarise the case

T : Things that went well

O : Opportunities to improve

P : Points to action and responsibilities

• Delayed activation of the Major Haemorrhage Protocol (MHP), leading to inadequate resuscitation.24
• Failure to recognise the need for timely resuscitative hysterotomy, which can improve maternal and foetal outcomes.24
• Underestimating airway challenges - anticipate difficult intubation, optimise pre-oxygenation and positioning, and be prepared for significant airway oedema and mucosal friability. Misinterpreting a normal PaCO₂—this may indicate impending respiratory failure rather than stability. Inadequate vascular access — ensure supra-diaphragmatic IV or intraosseous access for effective volume resuscitation and medication administration.24
• Overreliance on FAST ultrasound - it is less sensitive for detecting free fluid in pregnant patients compared to non-pregnant patients, which may delay diagnosis of intra-abdominal bleeding.24

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