Trauma During Pregnancy
Trauma is the leading cause of nonobstetric death in women of reproductive age. Six percent of all pregnancies are complicated by some type of trauma.
Mechanism of injury
Blunt abdominal trauma :
Blunt abdominal trauma secondary to motor vehicle accidents is the leading cause of
nonobstetric-related fetal death during pregnancy, followed by falls and assaults. Uterine
rupture or laceration, retroperitoneal hemorrhage, renal injury and upper abdominal injuries may also occur after blunt trauma.
occurs in 40-50% of patients with major traumatic injuries and in up to 5% of patients with minor injuries.
Clinical findings in blunt abdominal trauma :
Vaginal bleeding, uterine tenderness, uterine contractions, fetal tachycardia, late decelerations, fetal acidosis, and fetal death.
Detection of abruptio placentae.
Beyond 20 weeks of gestation, external electronic monitoring can detect uterine contractile activity. The presence of vaginal bleeding and tetanic or hypertonic contractions is presumptive evidence of abruptio placentae.
Uterine rupture :
Uterine rupture is an infrequent but life-threatening complication. It usually occurs after a
direct abdominal impact.
Findings of uterine rupture range from subtle (uterine tenderness, nonreassuring fetal heart rate pattern) to severe, with rapid onset of maternal hypovolemic shock and death.
Direct fetal injury
is an infrequent complication of blunt trauma.
a. The fetus is more frequently injured as a result of hypoxia from blood loss or abruption.
b. In the first trimester the uterus is well protected by the maternal pelvis; therefore, minor trauma usually does not usually cause miscarriage in the first trimester.
Penetrating abdominal trauma from gunshot and stab wounds during pregnancy has a poor prognosis.
Major trauma in pregnancy
Initial evaluation of major abdominal trauma
in pregnant patients does not differ from evaluation of abdominal trauma in a nonpregnant patient.
Maintain airway, breathing, and circulatory volume.
Two large-bore (14-16-gauge) intravenous lines are placed.
Oxygen should be administered by mask or endotracheal intubation.
O-negative packed red cells are preferred if emergent blood is needed before the patient's
own blood type is known.
A urinary catheter should be placed to measure urine output and observe for hematuria.
Deflection of the uterus
off the inferior vena cava and abdominal aorta can be achieved by placing the patient in the lateral decubitus position. If the patient must remain supine, manual deflection of the uterus to the left and placement of a wedge under the patient's hip or backboard will tilt the patient.
Following stabilization, a more detailed secondary survey of the patient, including fetal evaluation, is performed.
Minor trauma in pregnancy
Pregnant patients who sustain seemingly minimal trauma require an evaluation to exclude significant injuries. Common "minor" trauma include falls, especially in the third trimester, blows to the abdomen, and "fender benders" motor vehicle accidents.
The patient should be questioned about seat belt use, loss of consciousness, pain, vaginal bleeding, rupture of membranes, and fetal movement.
Physical examination should focus on upper abdominal tenderness (liver or spleen damage), flank pain (renal trauma), uterine pain (placental abruption, uterine rupture), and pain over the symphysis pubis (pelvic fracture, bladder laceration, fetal skull fracture).
A search for orthopedic injuries should be completed.
Management of minor trauma
The minor trauma patient with a fetus that is less than 20 weeks gestation (not yet viable), with no significant injury can be safely discharged after documentation of fetal heart rate. Patients with potentially viable fetuses (over 20 weeks of gestation) require fetal monitoring, laboratory tests and ultrasonographic evaluation.
A complete blood count, urinalysis (hematuria), blood type and screen (to check Rh status), and coagulation panel, including measurement of the INR, PTT, fibrinogen and fibrin split products, should be obtained. The coagulation panel is useful if any suspicion of abruption exists.
The Kleihauer-Betke (KB) test
This test detects fetal red blood cells in the maternal circulation. A KB stain should be
obtained routinely for any pregnant trauma patient whose fetus is over 12 weeks.
Regardless of the patient's blood type and Rh status, the KB test can help determine if
fetomaternal hemorrhage has occurred.
The KB test can also be used to determine the amount of Rho(D) immunoglobulin
(RhoGAM) required in patients who are Rhnegative.
A positive KB stain indicates uterine trauma, and any patient with a positive KB stain
should receive at least 24 hours of continuous uterine and fetal monitoring and a coagulation panel.
is less sensitive for diagnosing abruption than is the finding of uterine contractions on external tocodynamometry. Absence of sonographic evidence of abruption does not completely exclude an abruption.
Patients with abdominal pain, significant bruising, vaginal bleeding, rupture of membranes, or uterine contractions should be admitted to the hospital for overnight observation and continuous fetal monitor.
Uterine contractions and vaginal bleeding are suggestive of abruption. Even if vaginal bleeding is absent, the presence of contractions is still a concern, since the uterus can contain up to 2 L of blood from a concealed abruption.