Abdominal trauma in pregnancy: Clinical sciences

Abdominal trauma in pregnancy is any abdominal injury ranging from minor bumps to the abdomen to significant blunt trauma or penetrating injury. Penetrating abdominal trauma can lead to rupture of the uterus, and blunt trauma can cause shearing forces resulting in placental abruption. Trauma is the number one cause of nonobstetric maternal death with even seemingly minor traumas risking fetal injury.

Your first step in evaluating a patient presenting with abdominal trauma is to perform a CABCDE assessment to determine if they are unstable. If your patient is unstable, control hemorrhage and stabilize their airway, breathing, and circulation right away. This means you may need to intubate your patient. Obtain IV access, ideally by placing two large bore IVs to allow for adequate fluid resuscitation. Continuously monitor maternal vital signs, and remember…

You have two patients; so you must assess the fetus as well! Check the fetal heart rate, and if at a viable gestational age, perform continuous fetal monitoring; also assess for fetal movement. And since bleeding in the uterus can stimulate uterine contractions, you should assess for labor.

Then, assess the mechanism of injury to the maternal abdomen and fetus to determine your next steps. If the mechanism of injury is penetrating abdominal trauma, perform a focused history and physical exam; obtain labs including a CBC, PT, INR, PTT, and fibrinogen; obtain type and screen, which is important in case your patient requires transfusion; and perform a focused assessment with sonography in trauma, or FAST exam.

Your patient may report dizziness, anxiety, or tunnel vision due to significant blood loss; and they’re likely to have abdominal pain and contractions. A history of intimate partner violence is a risk factor for injury, especially if there’s access to weapons; so your patient may also report a gunshot or knife wound.

When it comes to the physical exam, expect hypotension and tachycardia, as well as an altered mental status to the point of being unconscious. Patients may look pale and their skin may feel cold or clammy due to acute blood loss. You might also find signs of an acute abdomen like rigidity, rebound pain, and guarding; and there may even be abdominal contents extruding through the area of injury.

If the penetrating injury has extended to the uterus, you might see vaginal bleeding as well as a tender, firm, hypertonic uterus. The trauma may cause blood to be shunted away from the uterus, which can lead to fetal bradycardia or recurrent late decelerations on the fetal heart monitor. If there’s blood in the uterus, you may notice high frequency, low amplitude uterine contractions on the tocometer.

As for labs, they might show anemia; low platelets; elevated PT, INR, and PTT; and a low fibrinogen. Finally, you may see blood in the pericardial cavity, abdominal cavity, or pelvic cavity on the FAST exam. With these findings, your diagnosis is uterine rupture with hemorrhage and shock.

Treatment is centered around prioritizing maternal stabilization to promote optimal outcomes for both your patient and the fetus, and includes IV fluids, blood transfusion, exploratory laparotomy to evaluate for internal injuries, and delivery of the fetus due to maternal instability. Finally, give Rh immune globulin if your patient is Rh-negative.

Alright, let’s talk about another injury mechanism, blunt abdominal trauma. Perform a focused history and physical exam; obtain labs including CBC, PT, INR, PTT, and fibrinogen, as well as a Kleihaeur Betke test, or KB for short, to identify fetal blood in the maternal circulation. Also, obtain type and screen and perform a FAST exam.

Your patient may report dizziness, anxiety, or tunnel vision, as well as abdominal pain and contractions. They may have a history of intimate partner violence, or they may have experienced a recent fall, which is most likely to occur in the second and third trimesters due to shifts in the center of gravity.

Another important risk factor is being involved in a high-speed motor vehicle crash especially if the seat belt is worn incorrectly across the abdomen. During pregnancy, the seat belt should be positioned under the gravid uterus and across the pelvis, which reduces pressure on the uterus; and the shoulder harness should lay across the clavicle and between the breasts. Other causes of injury during a motor vehicle crash include airbag deployment which can hit the abdomen, or rapid deceleration which subjects the placenta to a shearing force.