The Pregnant Abdominal Trauma Patient

Author: Tracy Evans, MBA, RN, EMT-P

Follow this link to review the "Call Review": 26 year old female sitting behind the wheel of her car. She is obviously pregnant, and her legs are entangled under the dash board. Her airbag has deployed but she was not wearing her seat belt.  She is awake, alert and complaining of abdominal pain and leg injuries.


Trauma is the leading cause of death in ages 1-44, so it stands to reason that it is the leading cause of death during most of the reproductive years.  Many of us are taught to assume that any female patient under 60 is capable of pregnancy.  Trauma is also the leading non-obstetric cause of disability in pregnant women. Fortunately, the incidence of injury to pregnant women is relatively low, with only 7% of patients estimated to be injured during pregnancy. (Knudson, 2000)  Frequency of accidental injury is greatest in third trimester, as balance and coordination are affected. Motor vehicle accidents account for 67% of all major injuries, followed by falls, and physical abuse (10-31%).

The most important thing to remember when caring for the critically ill pregnant female is that the resuscitation priorities are exactly the same as for the non-pregnant female or male patient. Airway, Breathing, Circulation: without these, both mother and fetus will die.

Anatomic and Physiologic Changes During Pregnancy:

Because trauma during pregnancy is not a common occurrence, providers may be unfamiliar with the normal physiologic changes in the obstetric patient and this can make assessment, management and resuscitation more difficult.


Respiratory rate may be slightly increased

Tidal Volume (the amount of air moved in and out of the lungs during each breath) increases by 40%

Vital Capacity (maximum amount of air exhaled from point of maximum inspiration) increases by 100 to 200 ccs

Arterial blood gases reveal a respiratory alkalosis caused by hyperventialtion

  • PaCO2 may decrease to 30 mmHg (normal 35-45mmHg)
  • PaO2 will increase to 101-104 mmHg (normal 80-100)



Cardiac output increases by 30% (1-1.5 L/minute) as the woman becomes hypervolemic and hyperdynamic. The expanding uterus requires 25% of the total cardiac output.

Heart rate increases by 15-20 beats per minute

As the pregnancy progresses, the heart is elevated and rotated to the left to compensate for the pressure exerted upward by the gravid uterus. As a result, the ECG may reveal flattened or inverted T waves in III, aVF, aVL.

Blood pressure decreases by 5 mmHg and hypertension is usually an indicator of an obstetrical emergency.

Venous pressure is increased in the lower extremities which leads to engorgement and edema. Compression of the aorta or vena cava may cause dizziness, discomfort or nausea.

The hematocrit decreases to 31-34% (normal 41- 50%.  The volume of packed red cells, or hematocrit, is the proportion of the volume of a blood sample that is occupied by red blood cells.) Anemia of pregnancy is casued by an increased plasma volume without a proportional increase in hemoglobin.

The fetus is compromised with a blood loss of 15-30%. Gradual losses are better tolerated and more difficult to detect. In fact, the first evidence of hypoperfusion in the mother may be fetal bradycardia or absent fetal movement noted during fetal assessment.

Hormonal changes can cause an increase in Fibrinogen, and clotting factors VII, VIII, IX, resulting in hypercoagulability and predisposes the patient to deep venous thrombosis and disseminated intravascular coagulopathy (DIC)


Increased risk of vomiting and aspiration due to a decrease in gastric motility which causes an increase in emptying time. Hormonal changes in the second and third month relax the esophageal sphincter, which also increases the risk of aspiration.

Rebound tenderness, which in the normal abdomen, indicates peritoneal membrane irritation, may be absent in the obstetric patient because of the gradual compression of the viscera and stretching of the abdominal wall by the uterus.

The gravid uterus has been shown to be protective to intra-abdominal organs. Most commonly, hemorrhage will be retroperitoneal; however, spleen, kidney, and liver remain the most commonly injured organs.


Urinary frequency is increased during pregnancy for two reasons: compression of the bladder and an increased glomerular filtration rate. In the third trimester, the bladder is elevated and displaced anteriorly out of the pelvis and into the abdomen, predisposing it to increased injury. The supporting ligaments are slowly stretched, which may cause pain in some women.


Hormonal changes occur to facilitate the childbirth process and cause a softening of most joints and relaxation of the sacroiliac joint. By the third trimester, the symphysis pubis is widened from approximately 4.3 mm to 7.8 mm. (Neufeld, 1998) Fortunately, these changes also make the pelvis less susceptible to fracture. Fracture in the second and third trimester can damage pelvic blood vessels that are engorged by increased blood volume and decreased venous return from inferior vena cava compression.

Specific Injuries:

Head injury is the major cause of maternal death .  (Pearlman, 1990) The major causes of fetal death are death of the mother, shock in the mother, disruption of the placenta, and direct injury to the fetus.  The physiologic changes in pregnancy, predispose the obstetric patient to the following injuries:

Uterine Injury

As the gravid uterus increases in size, it is prone to tear, rupture or puncture.

Despite what we may fear, uterine rupture is rare and may occur only in patients with extreme compression injuries or with a history of cesarean sections. (ENA, 2000) It may be associated with bladder rupture, and early detection and management may be the only way to prevent maternal hemorrhage and fetal death. It can rarely be repaired and may require hysterectomy. The signs and symptoms may be:

  • Abdominal pain or acute pain followed by no pain
  • Uterine tenderness
  • Change in the shape of the uterus
  • Difficulty in assessing fundal height
  • Vaginal bleeding
  • Maternal hemorrhage or hypovolemia

Abruptio Placenta

The partial or total separation of the placenta from the wall of the uterus. It is a common cause of fetal death following motor vehicle crashes. In fact, two-point restraints increase the risk of abruptio placentae over that of the three-point restraint systems. It can occur immediately or as long as 48 hours after the traumatic event. Placental abruption occurs in up to 50% of patients with major traumatic injuries and up to 5% of patients with minor injuries. The signs and symptoms can be vague, especially with a partial abruptio placenta. Ultrasound may be the only definitive diagnostic tool, so the provider should observe for possible signs and symptoms:

  • vaginal bleeding or hypovolemia
  •  increased fetal heart rates, if audible with a stethoscope or doppler
  • uterine tenderness
  • uterine rigidity or tetany
  • premature labor
  • abdominal pain or cramping
  • fetal distress
  • increasing fundal height (the level of the uterus in the abdomen)

Preterm Labor

This is the most frequent complication in the obstetric trauma patient. (Neufeld, 1998) It is easy to recognize in alert patients, but may be difficult to detect in the unconscious, intubated or sedated patient. The signs and symptoms include:

  • Uterine contractions > 6 per hours
  • Back pain
  • Clear or bloody vaginal discharge
  • Cervical dilation or effacement on pelvic exam. This, of course, should be performed only by a qualified physician, nurse midwife, or obstetric nurse.

Diaphragmatic Rupture

The uterus enlarges during pregnancy and increases the pressure of the abdominal, retroperitoneal and pelvic organs against the diaphragm.

Bladder Injury

As the uterus enlarges, the bladder is displaced upwardly and is compressed. It is less well-protected during the second and third trimesters and can be injured.

Pelvic Injuries

Fractures of the pelvis can cause increased hemorrhage if one of the engorged pelvic vessels is damaged.

Fetal Injury

Fetal injury is more common in the third trimester when the head is relatively fixed in position in the pelvis and there is less amniotic fluid present to absorb energy or buffer the transfer. The fetus can sustain skull fractures, intracranial injuries, hepatic, splenic and clavicle injuries. (Esposito, 1989) Penetrating wounds injure the fetus in up to 70% of cases and cause maternal visceral injuries in 19% of cases


As in any trauma case, the ABCs of trauma resuscitation must be followed in treating pregnant victim. The best way to treat the fetus is to treat the mother.  Therefore the approach to the pregnant patient is not different than the approach to the non-pregnant patient.

  • Supplemental oxygen always should be placed on the mother as the fetus is extremely sensitive to hypoxia.
  • The decision to intubate is largely unaffected by pregnancy. Use of rapid-sequence medications in pregnancy is not well studied; however, there are no absolute contraindications.
    • Avoid supine hypotension syndrome.
    • By placing rolled towels beneath the spinal board, paramedics should tilt the patient to the left 15 degrees in order to prevent compression of inferior vena cava by gravid uterus.
  • Initiate IV therapy, with one or two large-bore catheters and Normal Saline or Lactated ringers according to local protocol as the relative hypervolemia of pregnancy allows for 30-35% loss of blood volume without development of hypotension.
  • If warranted, auscultation of fetal heart tones may be performed as part of initial fetal assessment and to reassure the mother. The use of a doppler may be necessary and
  • MAST (Military Anti-Shock Trousers)
    • Class III intervention (inappropriate, possibly harmful) for gravid patients. If used, only inflate leg compartments


A high index of suspicion needs to be in the forefront of the EMS provider’s thinking when caring for the pregnant patient.  The physiologic changes associated with the pregnant state can "mask" the signs and symptoms of a compensated shock state.  The body will sacrifice the fetus when compensating for shock, therefore it is important to remember that the vital signs and clinical appearance of the mother simply does not reflect the potential or actual compromise of the fetus from trauma.  Maintain a high index of suspicion and treat the mother aggressively and transport promptly - it’s the only way to guarantee the fetus is receiving treatment.


  • Emergency Nurses Association. Trauma Nursing Core Course (Provider Manual). Chicago. 2000.
  • Esposito, TM, Gens, DB, Smith LG, Scorpio, R, Buchman, T. Trauma during pregnancy: A review of 79 cases. Arch Surg. 1991;126:1073-1078.
  • Knudson, M, Rozycki, CS, and Strear, CM. Reproductive system trauma. In: Mattox, KL,
  • Feliciano, DV, Moore, EE, eds. Trauma. 4th ed. New York: McGraw-Hill; 2000:879-906.
  • Neufeld, JD. Trauma in pregnancy. In: Rosen, P, Barkin, RM, eds. Emergency Medicine: Concepts and Clinical Practice. 4th ed. St. Louis: Mosby-Year Book;1998:368-81.
  • Perlman, MD, Tintinalli, JE, Lorenz, RP. Current concepts: Blunt trauma during pregnancy. N Eng J Med. 1990; 323:1609-1613.