Trauma in Pregnancy

trauma is the leading nonobstetric cause of maternal mortality
most common mechanisms of injury are falls or MVAs
pregnant women who sustain trauma have a higher incidence of spontaneous abortion, preterm labor, fetomaternal hemorrhage, abruptio placentae, and uterine rupture than age-matched pregnant controls
best treatment for the fetus is optimal resuscitation of the mother

uterus remains intrapelvic until the 12th week, protected by the bony pelvis
by 20 weeks, the uterus is at the umbilicus, and the bowel is being pushed cephalad
by 34 – 36 weeks, the uterus reaches the costal margins

plasma volume increases throughout pregnancy
a smaller increase in RBC mass also occurs, resulting in a decreased hematocrit level (physiologic anemia of pregnancy)
in late pregnancy, a hematocrit level of 31% - 35% is normal
a healthy pregnant woman can lose 30% of her blood volume (1200 – 1500 cc) before tachycardia and hypotension ensue
however, as a response to the blood loss, uterine vascular resistance greatly increases
this results in decreased uterine blood flow and decreased fetal oxygenation
thus, fluid resuscitation should be started early even in a normotensive pregnant trauma patient

cardiac output is increased in pregnancy, with the uterus and placenta receiving 20% of the cardiac output during the 3rd trimester
however, in the supine position during late pregnancy, uterine compression of the vena cava can decrease cardiac output by 30%
pregnant trauma patients should be placed in the left lateral decubitus position
if spinal cord injury is suspected, the patient may be secured to a backboard and then tilted to the left

heart rate increases by 10 – 15 beats/min during pregnancy
SBP and DBP fall by 5 – 15 mm Hg
these facts must be recognized when interpreting vital signs in a pregnant trauma patient

minute ventilation increases during pregnancy
PCO₂ of 30 mm Hg during late pregnancy is normal
PCO₂ of 35 – 40 mm Hg may indicate impending respiratory failure during pregnancy
oxygen consumption during pregnancy is increased
it is imperative to maintain arterial oxygenation during resuscitation of injured pregnant patients (aim for an oxygen saturation of 95%)

eclampsia is a complication of late pregnancy that can mimic head injury
neurological and obstetrical consultation may be necessary to help differentiate between eclampsia and other causes of seizures

always the first priority
patient’s right side should be elevated by 15 – 30 degrees
even with normal vital signs, aggressive fluid resuscitation is indicated to support the hypervolemia of pregnancy
vasopressors are an absolute last resort since they further reduce uterine blood flow, worsening fetal hypoxia

goal is to detect serious maternal injuries
main cause of fetal death is maternal shock and maternal death
indications for FAST and CT scan are the same as in nonpregnant patients
if DPL is done, the catheter should be placed above the umbilicus using the open technique

OB-GYN should be consulted early
patient needs a formal pelvic examination, ideally by an OB-GYN
significant findings include vaginal bleeding, amniotic fluid, cervical effacement and dilation, fetal presentation

partial or total separation of the placenta from the uterine wall
2nd most common cause of fetal death
vaginal bleeding occurs in 70%
other signs include abdominal pain, uterine tenderness, frequent uterine contractions, uterine irritability/tetany
uterine ultrasound may be helpful in diagnosis, but it is not definitive
late in pregnancy, abruption may occur following minor injuries

suggested by abdominal tenderness, guarding, rebound tenderness, shock
other abnormal findings include abnormal fetal lie, easy palpation of fetal parts
x-ray findings include free intraperitoneal air, abnormal fetal position

maternal heart rate > 110, Injury Severity Score > 9, fetal heart rate > 160 or < 120, ejection from vehicle, motorcycle or pedestrian collisions, and evidence of placental abruption
fetal heart tones can be auscultated with Doppler ultrasound at 10 weeks
continuous fetal monitoring can be performed at 20 – 24 weeks
patients with no risk factors should have continuous fetal monitoring for 6 hours
patients with risk factors should be continuously monitored for 24 hours

may occur after amniotic fluid embolization or extensive placental separation
consumptive coagulopathy
fibrinogen levels are elevated during pregnancy, and so a normal fibrinogen level may represent early DIC
treatment is emergent uterine evacuation and replacement of clotting factors

0.01 mL of Rh-positive blood will sensitize 70% of Rh-negative patients
all pregnant Rh-negative trauma patients should receive Rh immunoglobulin therapy unless the injury is remote from the uterus (distal extremity injury)
immunoglobulin therapy (RhoGAM) should be started within 72 hours of injury