Trauma is the leading cause of nonobstetric death in expectant mothers, affecting 7 percent of all pregnancies; most often trauma occurs in the third trimester. Major trauma has been associated with 7 percent of maternal and 80 percent of fetal mortality.
Motor vehicle crashes are the most common cause of blunt trauma in pregnancy, representing 50 percent of cases. Falls due to instability, especially late in pregnancy, represent another 22 percent of injuries.
"Pregnant women tend to walk differently and have different balance, so they may have some risk of ankle or knee injury in a fall," says Erica A. Loomis, M.D., a trauma surgeon at Mayo Clinic's campus in Rochester, Minnesota. "When pregnant women do fall, they try to protect their abdomens, so they may twist in a way that could lead to other injury."
Most trauma is accidental or unintentional. Though the rates of intimate partner violence or assaults rise during pregnancy, these account for only 2 to 3 percent of total traumas in pregnancy.
When injury occurs, the mother's pregnant anatomy provides excellent fetal protection, with the thick uterine walls and amniotic fluid helping prevent shock. However, the fetus becomes more exposed to potential injury as it grows and the uterus leaves the bony protection of the pelvis.
Risk of fetal and maternal death from trauma
Placental abruption is the most common cause of fetal death from trauma in pregnancy. Force from trauma can sheer the placenta from the uterine wall and lead to fetal demise. Uterine rupture, though rare, usually occurs in the third trimester and is associated with high risk of fetal and maternal mortality.
"Even a minor injury can lead to fetal loss," says Dr. Loomis. "Any pregnant woman who's been traumatically injured should be checked out by an OB-GYN just to ensure there's no vaginal bleeding, premature rupture of membranes, uterine contractions — anything that can lead to complications."
Missing early signs of shock in a pregnant patient also can lead to a high risk of maternal and fetal mortality.
Managing trauma in pregnancy
Managing a case of trauma in pregnancy can be an emotionally charged situation.
"Any time you are dealing with two patients coming in as one, you are dealing with a higher stress situation," says Dr. Loomis, adding that sometimes expectant mothers facing traumatic injury can be hysterical, and family members with passions running high can be distracting.
If available, request a social worker, chaplain or available nurse to help manage family members and their needs.
Traumatically injured pregnant women should initially be treated the same as their nongravid counterparts. The first goal is to assess the maternal airway, breathing and circulation and establish maternal-cardiopulmonary stability; resuscitating the mother will optimize fetal outcomes.
Consulting with OB-GYN colleagues can be invaluable. In addition, providers should be mindful of anatomical changes from pregnancy that affect how expectant patients look in the trauma bay. Blood volume expands, blood pressure declines, carbon dioxide decreases, heart rate runs higher, tidal volume increases and respiratory rate increases.
Providers also need to remember to avoid becoming distracted by the fetus when treating expectant mothers with traumatic injury.
"The best way you're going to get both of these individuals — fetus and mom — through this traumatic event is to save mom," says Dr. Loomis. "So, whatever needs to be done to save mom is really what needs to be done, instead of focusing on 'What about the fetus?' The fetus is unlikely to survive if mom doesn't survive.
"It happens a lot that providers focus on the fetus and miss other key things — lifesaving things — that should be addressed," she says, noting that evaluation of the fetus should commence only after the mother has been stabilized.
Beyond distraction by the fetus, there are several other potential pitfalls to avoid while treating expectant mothers, such as:
Women who are pregnant may not tolerate customary supine positioning on a backboard. The inferior vena cava may be compressed by the gravid uterus, causing the patient to be at risk of supine hypotension syndrome. To avoid this risk, place the patient on the board tilted so the left side is slightly down and the right side is slightly up.
Inflating injury severity score
The same injury severity score applied to nonpregnant women also applies to expectant mothers. Scores should not be elevated simply because the patient is pregnant.
Not recognizing respiratory failure
In an expectant mother, tidal volume gets larger and respiratory rate changes to accommodate a growing uterus. Thus, for a pregnant female, even what look like normal blood gas or lab values may actually be signs of impending respiratory failure. Early intubation and airway management can be lifesaving.
Giving insufficient amount of volume resuscitation
If a hospital has blood supply, providers should administer it if clinically indicated, while recognizing pregnant women need larger volume than a nonpregnant female.
Conducting a vaginal exam
A vaginal exam is crucial to know if issues are present, especially vaginal bleeding, presence of umbilical cord or loss of amniotic fluid, for appropriate patient management.
Missing early signs of shock
Pregnant females can physiologically compensate very well and may not appear to be in shock until they have suffered significant blood loss; thus, providers can inadvertently bypass a critical window for administering ample volume resuscitation with IV fluid or blood.
"Even if mom looks good and has normal vital signs, there can be signs of fetal distress," says Dr. Loomis. "The mom's body doesn't consider the uterus a vital organ, so blood will be shunted away from the uterus if that's what's needed, which can lead to significant and abrupt fetal compromise."
Also essential to the care of pregnant females with traumatic injury is performing blood typing to determine Rh (D) status. Rh (D)-negative women with major trauma who are not already alloimmunized should receive anti-D immune globulin. A Kleihauer-Betke test can be performed to determine whether any maternal-fetal blood exchange has occurred.
Due to difficulty determining whether direct injury to the fetus has occurred, asking the mother about fetal movement and utilizing monitors can provide additional needed data beyond clinical exam.
Generally, providers in the trauma bay can administer medications to pregnant women just like any other trauma patient. Dr. Loomis explains there is limited data associated with the risks of modern radiographic imaging to the unborn fetus.
"Outside the first trimester — and certainly by the third trimester — the risk is fairly limited," she says, noting a very small risk of childhood leukemia early in pregnancy and a small risk for intrauterine growth restriction later in pregnancy.
"Overall, the risks versus benefits should be weighed, and providers should proceed accordingly," Dr. Loomis says. "Risk of radiation to the fetus exists, but if the mother dies of an unrecognized injury, the fetus won't survive, either."
After examination and treatment in the trauma bay, providers should proceed with admission and care of the identified injuries. If no injuries are identified, pregnant patients should be monitored for six hours, or even longer in higher level injury cases or fetal distress.
The question of transfer
Whether a pregnant patient who has suffered trauma should be transferred to a higher level of care depends on her pregnancy stage and the treating hospital's resources. A few key questions to determine need for transfer include:
- Is the needed blood supply available?
- Is vaginal bleeding or membrane rupture present that may require neonatal delivery?
- Is the local obstetrician comfortable monitoring this patient?
- Does she need providers who can manage both the trauma and the pregnancy?
- If this patient wasn't pregnant, would we keep her as a trauma patient anyway?
"Just take the pregnancy out of the picture for a minute, and transfer decisions will become more apparent," says Dr. Loomis.