Continuing Education Activity
Trauma in pregnancy can ranges from mild, for example trauma associated with a single fall from standing height or hitting the abdomen on an object such as an open desk drawer, to major, for example trauma associated with penetrating injury or high force blunt motor vehicle accident. This activity reviews the evaluation and management of trauma in pregnancy and highlights the role of interprofessional team members in collaborating to provide well-coordinated care and enhance outcomes for affected patients and families.
- Identify the most common causes of pregnancy trauma.
- Describe the exam that should be done in pregnant patients who have undergone trauma.
- Review how to manage pregnant patients who have undergone trauma.
- Explain the importance of improving coordination amongst the interprofessional team to enhance care for pregnant patients who have undergone trauma.
Trauma in pregnancy has a wide spectrum, ranging from mild (single fall from standing height or striking the abdomen on an open drawer) to major (penetrating or high force blunt injury such as motor vehicle accident). Trauma in pregnancy has dramatically increased in the past 25 years and is now the number one cause of non-obstetrical maternal death in the United States. With major trauma there is a 40 to 50% risk of fetal death. Even with minor trauma, if it occurs during the first or second trimester there is an increase to delivering a child with prematurity or low birth weight. Although infrequently encountered in the clinical setting, emergency medicine physicians, trauma surgeons, and OBGYN’s should be aware of and prepared to manage a variety of complications associated with trauma in pregnancy. With sufficient knowledge of normal maternal physiology and potential pregnancy-related injury patterns, the physician facing a pregnant trauma victim will be better equipped to manage them, thus resulting in reduced morbidity and mortality.
Etiology of trauma in pregnancy may be multifactorial. The physics of the growing abdomen result in an imbalance, which increase frequency of maternal falls from standing or from height, such as stairs. Further the clinician must maintain a heightened suspicion for non-accidental causes either self-inflicted or other. Domestic violence increases during pregnancy, placing the mother and the fetus at obvious risk for injury. Domestic violence occurs in 4 to 8% of pregnancies and is associated with 5% risk of fetal death. The normal physiology of the pregnant mother complicates evaluation and management of trauma in pregnancy. The gravid uterus is particularly susceptible to penetrating and blunt force trauma to the abdomen. Motor vehicle accidents account for 50% of all traumatic injuries during pregnancy and 82% of trauma related fetal death. The main reason for this equates to the improper use of seat belts. The lap belt needs to be placed under the dome of the abdomen and across the pelvis to reduce pressure on the uterus during a motor vehicle collision. The shoulder harness should lay across the clavicle and between the breasts. 
Trauma is sustained in 8% of all pregnancies. Regardless of mechanism, trauma can be life threatening for both the mother and fetus. Rapid evaluation and treatment of the mother in trauma should be even further heightened, as maternal shock is associated with an 80% fetal mortality. Pelvic fracture is the most common maternal injury that results in fetal death. In review of pregnant females with sustained pelvic fracture by Leggon et al, rate of fetal mortality was 35%. Casuses of death included direct fetal injury (20%), placental abruption (32%), and maternal shock (36%). Dilated vasculature due in part to maternal physiologic changes, places mothers at increased risk for hemorrhage following pelvic fractures. With mortality in these mothers being as high as 9%. The most devastating injuries following direct blunt trauma include placental abruption and uterine rupture. Abruption is thought to complicate 1-6% of minor injuries and up to 50% of major injuries. Uterine rupture is overall rare, occurring in less than 1% of pregnant trauma patients, and is most commonly associated with direct impact with sustained force to a previously scarred uterus. In contrast to blunt trauma, maternal mortality is more favorable following penetrating injury as the gravid uterus serves as protection to the maternal internal organs. Conversely, fetal mortality following penetrating injury has been reported to be as high as 73%. 
Anatomic and Physiologic Changes in Pregnancy. To be able to recognize abnormal vital signs and injuries in a pregnant patient, normal anatomic and physiologic changes in pregnancy must be understood. Multiple organ systems undergo changes during pregnancy, the major, pertinent systems are discussed herein.
Abdominal Changes. The tone of the lower esophageal and gastric motility is reduced in pregnancy. This leads to reflux and retained food contents in the stomach, respectively. Because of these factors, there is an increased risk of aspiration, especially during intubation. The peritoneum stretches markedly and by the third trimester becomes much less sensitive to peritoneal irritation. Even in patients with traumatic hemoperitoneum, they may not exhibit abdominal tenderness on examination due to the peritoneal stretching and insensitivity (AHC media, trauma reports. Current Concepts in the Management of the Pregnant Trauma Patient. Author: Dennis Hanlon, MD). The uterus eventually becomes the largest intraabdominal organ. Its walls become thin and susceptible to injury. Blood flow increases from a non-pregnant state of 60 ml/min to an impressive 600 ml/min at term. As in the typical blunt trauma patient, the spleen remains the most commonly injured organ.
Hematologic Changes. Both the plasma volume and the red cell mass increase throughout pregnancy. Plasma volume doubles by the end of the third trimester, however, in much higher proportion than the red blood cell mass increase. This results in dilutional anemia of pregnancy. The normal hemoglobin is 10-14 grams per deciliter by the term. The liver becomes hypermetabolic, increasing production of coagulation factors and fibrinogen. With this production, the patient is now more at risk for deep vein thrombosis and disseminated intravascular coagulation (DIC). DIC panels must be interpreted with caution. Because it is expected to have elevated fibrinogen levels at term, a normal fibrinogen level may indicate DIC.
Pulmonary Changes. Respiratory rate (RR) x tidal volume (TV) = Minute ventilation (MV). RR does not change during pregnancy. Counterintuitively, TV is increased by 40%, leading to a 40% increase in MV. This leads to a lowered partial pressure of carbon dioxide (PCO) of 30 mmHg (normal values are in the range 35-45 mmHg), resulting in a chronically compensated respiratory alkalosis. This must be taken into account when evaluating a blood gas. The diaphragm is elevated by approximately 2-4 cm at term. This is essential to know when performing a tube thoracostomy. Chest tubes should be placed in the same mid-axillary line, however, 2 cm higher to avoid potential puncture into the liver or spleen. Lastly, the Mallampati score, an airway assessment score used prior to intubation, is an estimated distance from the base of the tongue to the roof of the mouth. Mallampati classification ranges from 1-4: 1 denoting all inner oral cavity structures visible, to 4, wherein only the hard palate is visible. The Mallampati score increases throughout pregnancy, leading to a greater percentage of levels 3 and 4. Given all of these pulmonary changes, a pregnant trauma has potential to result in a difficult airway scenario.
Cardiovascular Changes. Pregnancy-related cardiovascular changes require careful interpretation of the vital signs in the trauma patient. Pulse in the 3rd trimester elevates 15-20 beats per minute. The blood pressure goes down by 15-20 mmHg, however, returns to normal during the 3rd trimester. Any sign of hypotension should be evaluated immediately given this return to the normal level. It should not be attributed to the pregnant state as this is an interpretation of exclusion in the setting of trauma. Finally, as noted previously, the plasma volume rises by 50%, thus leading to a potentially delayed recognition of shock. By the time the maternal blood pressure falls, the patient may have already sustained a 30% blood loss.
Pregnancy Related Injuries. As with any trauma, certain injury patterns are likely. There are injuries unique to pregnancy that must be considered in addition to these.
Premature Labor. Premature labor is defined as the presence of uterine contractions occurring at less than 36 weeks’ gestation (premature) accompanied by cervical changes (labor). Although trauma patients may feel pain similar to real labor contractions, these pains may not represent contractions. Toconometry is indicated to determine if the contractions are real. The most common cause is placental abruption (see below). If contractions are present, the diagnosis of placental abruption must be considered and investigated, as well as uterine rupture and other hemorrhage. If present, correction of hypoxia and hypovolemia should occur as these are common causes of premature labor.
Placental Abruption. Placental abruption is the leading cause of fetal death not related to maternal death. It occurs in 1-5% of minor trauma. It is important to note that the classic triad of vaginal bleeding, abdominal pain, and uterine irritability may not be present. The edges of the placenta may encase the bleeding internally, in addition to the peritoneum being markedly insensitive given the massive stretching near term. Ultrasound may be helpful in the diagnosis but is not sensitive. If the ultrasound does not reveal abruption, the diagnosis is not ruled out. Regardless, toconometry is required for minimum 4 hours and may be extended by the obstetrical team for a multitude of reasons.
Amniotic Fluid Embolus. Uncommon and catastrophic, the pathophysiology of amniotic fluid embolus is currently poorly understood. The patient may present much like a massive pulmonary thrombotic embolus. There is no specific treatment for this entity, with exception of supportive care, intubation, vasopressors, and transfusion.
Uterine Rupture. Although a rare complication of trauma (0.06%), fetal mortality approaches 100% when present. It most often occurs in the 3rd trimester. Because of the high amount of force required to cause uterine rupture, it is commonly associated with pelvic fractures and bladder injuries. The classic presentation is dramatic; abdominal pain, distention (due to the unfolding of the fetus), palpable fetal parts, and shock. However, given the peritoneum's insensitivity in the 3rd trimester, there may be no pain present. High index of suspicion accompanied by prompt recognition is critical. Treatment is exploratory laparotomy, delivery of fetus and supportive care.
History and Physical
The standard trauma algorithim should be followed when evaluating a pregnant patient who has experienced trauma. Trauma assessment and resuscitation priorities are the same as in the nonpregnant woman but modified to thereafter address changes that occur in the later stages of pregnancy. This includes a primary, secondary, and tertiary survey. Attention should be paid to the vital signs as they change throughout normal pregnancy, noting changes to physiology as described previously. If alert and able, all women of child bearing age involved in trauma should be questioned on feasibility of pregnancy and Beta-human chorionic gonadotropin (HCG) testing obtained unless expressed inability to conceive. Prior history of preterm labor, placental abruption and placenta previa are as well important to illicit if able. Likewise urgent OBGYN consultation is recommended especially when the trauma patient is of gestational second or third trimesters.
When the airway is compromised or rapid sequence intubation is deemed necessary, lower doses of succinylcholine are required due to the lower concentrations of pseudocholinesterase during pregnancy. It is important to avoid hypotension and provide supplemental oxygen due to the significant fetal vulnerability to hypoxia.
Clinical assessment alone may identify potential injury to the uterus or fetus. Concerning findings include: penetrating injury to the abdomen, vaginal bleeding, ruptured membranes, bulging perineum, presence of contractions and an abnormal fetal heart rate or rhythm. Vaginal bleeding is abnormal before labor and can be indicative of placental abruption, early labor, premature cervical dilation, or placentra previa. Rupture of the amniotic sac should be suspected when there is cloudy, white or green discharge, which leads to increased risk of infection. A ruptured amniotic sac may also lead to umbilical cord prolapse, which itself is an obstetric emergency requiring immediate cesarean section. If hemodynamically able, the pelvic examination should therefore include a speculum exam.
In addition, the abdomen should be palpated to determine the level of uterine height. Measurement of fundal height allows estimation of gestational age, for which may be the only insight into gestational age in an unresponsive patient. Between eight to twelve weeks, the uterus begins to enter the abdominal cavity, arising above the pubic symphysis. At 20 weeks, it approaches the level of the umbilicus. At this point, the uterus should grow at approximately one finger’s breadth until 40-weeks gestation. The uterus will reach the sternum at 36 weeks and then become lower as the fetal head engages into the pelvis. Discrepancy between the fundal height and known gestational age should alert the clinician to an abnormality, concerning for uterine trauma or a preexisting condition such as multiple pregnancy or intrauterine growth retardation.
Again, standard ATLS algorithm and protocol should guide evaluation and resuscitation in the trauma patient who happens to be pregnant.
Fetal heart tones can be auscultated with a stethoscope at 20 weeks gestation; prior to this, a Doppler is needed. Evaluation of the fetus itself is best performed with toconometry, which is the most accurate means to detect fetal distress. Fetal heart tones can be detected as early as 12 weeks of gestation and are normally between 110 and 160 beats per minute (bpm). Initially, fetal hypoxia manifests as tachycardia, but as the arterial oxygen content decreases, the fetus ultimately becomes bradycardic. Therefore any sustained rate below 120 bpm should be recognized as fetal distress. If fetal distress is detected, then maternal blood loss must be suspected. Monitoring of fetal heart rate should be initiated on any woman greater than 24 weeks gestation, and is typically recommended for 4 to 6 hours duration after the initial presentation.
Radiographic imaging is often indicated in pregnant patients, especially those whom have sustained traumatic event. However, due to the fear of potential teratogenic and deleterious effects of ionizing radiation practitioners are often hesitant to order appropriate studies. The fear of radiation exposure should not take precedent over quickly establishing the correct diagnosis to allow expeditious treatment initiation. In trauma, as in all other scenario’s, the care of the patient, not the fetus should take priority, and take precedent over risk of ionizing radiation. The effects of radiation exposure on the fetus depend on the gestational age and the amount of radiation. In general the earlier the gestational age, the higher the risk. Specifically, abdominal X-rays submit 200mrad (0.1 to 0.3 rads) of ionizing radiation to the fetus while abdominal and pelvic computer tomography (CT) scan subjects the fetus to 3-4 rads. The accepted accumulated dose of ionizing radiation during pregnancy is less than 10 rads, with no single diagnostic study to exceed 5 rads. Between 8 to 15 weeks gestation high-dose radiation (>10 rads) may lead to intra-uterine growth retardation and central nervous defects. Beyond 15 weeks, there appears to be no dose dependent effects such as fetal loss or congenital defects. Stochastic effects, such as the subsequent risk of cancer or leukemia are increased with exposure of 1 rad or more. The rate of such effect is approximately 1 for every 500 high-dose exposures. Effort should be taken to decrease unnecessary scans, reduce the overlap of body sections, and avoid multiple passes when possible.
The risk of a missed injury or delay in diagnosis is much greater to the fetus than the risk of radiation. As such the American College of Obstetricians and Gynecologists (ACOG) has submit the below guidelines for diagnostic imaging during pregnancy:
- Women should be counseled that X-ray exposure from a single diagnostic procedure does not result in harmful fetal effects. Specifically, exposure to < 5 rads has not been associated with an increase in fetal anomalies or pregnancy loss.
- Concern about possible effects of high-dose ionizing radiation exposure should not prevent medically indicated diagnostic x-ray procedures from being performed on a pregnant woman. During pregnancy, other imaging procedures not associated with ionizing radiation (eg, ultrasonography, MRI) should be considered when appropriate.
- Utrasonography and MRI are not associated with known adverse fetal effects.
- Consultation with an expert in dosimetry calculation may be helpful in calculating estimated fetal dose when multiple diagnostic x-rays are performed on a pregnant patient.
- The use of radioactive isotopes of iodine is contraindicated for therapeutic use during pregnancy.
- Radiopague and paramagnetic contrast agents are unlikely to cause harm and may be of diagnostic benefit, but these agents should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Adjunct imaging modalities include ultrasonography (US) and magnetic resonance imaging (MRI). US in form of the extended focused abdominal sonography in trauma (eFAST) should still be incorporated during trauma secondary survey. In a retrospective cohort of more than 2300 FAST exams the sensitivity and specificity showed no significant difference between detection of free fluid between pregnant and non-pregnant patients. This tool as in other trauma scenarios allows potential rapid identification of hemopneumothorax, pericardial tamponade and fluid in Morrison’s pouch or the splenorenal recess. Isolated pelvic free fluid as detected by ultrasound however is of unclear clinical significance in the pregnant patient. MRI is considered a good imaging modality in pregnancy due to its lack of ionizing radiation and specificity however its use in the emergent setting is limited by availability, and timely duration making its use in the trauma patient often non practical. 
Treatment / Management
Advanced Trauma Life Support principles remain the same whether the patient is non-gravid or full-term. As always, taking care of the maternal patient will, in turn, take care of the fetus. The best early treatment of the fetus is the optimal resuscitation of the mother. Upon determining of gravidity consultation with obstetrics is critical. Nearly all female patients between the ages of 10 and 55 years warrant Beta-human chorionic gonadotropin (HCG) testing. Transfer to an appropriate trauma center with applicable obstetrical specialized care has demonstrated improved maternal and neonatal outcomes post injury as opposed to non trauma centers.
The positioning of the patient to avoid or alleviate aortocaval compression syndrome, also known as a supine hypotensive syndrome, may be necessary. Woman in the second and third trimester should thus be placed onto their left side with a 15-degree bump or roll placed behind them for support to assist in displacing the uterus from vena cava compression, allowing increase in venous return and thus cardiac output.
The Rh blood type of the patient should be sought. If maternal negative, there is a chance of developing iso-immunization and compromising further pregnancies. Rh Immunoglobulin (RhoGham) should be administered regardless of mechanism, including fall from standing, as maternal Rh sensitization will occur at 0.01-0.03 ml in 70% of Rh negative patients. The dose of Rh Immunoglobulin is dependent upon the gestational age. At less than 12-weeks gestational age, 150mcg is indicated. At greater than 12 weeks, 300 mcg is indicated. The amount will need to be increased if feto-maternal hemorrhage is marked, in massive blunt force abdominal trauma. This is determined by the Klei-Hauer Betke test. This test is an acid elution assay on blood drawn from the maternal patient. After lysing cells with acid, it shows the amount of fetal blood in the maternal system. Note that this test has a threshold of 5 ml of maternal-fetal hemorrhage, but iso-immunization can occur at 0.01 ml. Therefore, this test should be utilized to determine not if, but rather how much, additional Rh Immunoglobulin is required.
Maternal vital signs are less sensitive. If hypotension is present, immediate investigation and treatment must ensue. In cases of hypovolemic shock, the mother will shunt blood from her fetus. Further, the placenta is highly sensitive to catecholamines and vasopressors alike. Early aggressive intravascular repletion and volume resuscitation is thus paramount and permissive hypotension should be avoided in this population. Similaryl vasopressors should be used sparingly, with knowledge that this will further compromise placental blood flow. Similar to the non-pregnant female, blood product resuscitation should proceed with a 1:1:1 component ratio. In instances of severe hemorrhage within 3 hours from trauma, tranexamic acid (TXA) is deemed safe, and should likewise be utilized. For those whom require urgent central venous access, femoral catheters should be avoided when able, again due to potential uterine compression of the vena cava reducing venous return. Special consideration should as well be taken in those requiring thoracostomy tube placement. In later terms of pregnancy, the diaphragm may rise to an additional 4 cm, thus the inserting clinician should plan on an insertion site of 1 to 2 intrercostal spaces higher than traditional placement to avoid intra-abdominal placement.
Indications for exploratory laparotomy are the same in the pregnant patient as in the nonpregnant trauma victim, however it is important to note that laparotomy alone is not an indication for cesarean section. During laparotomy the uterus should obviously be handled with care, being careful not to twist or place excess traction, as this may lead to potential vascular compromise. With adequate resuscitation, the fetus should tolerate the operative procedure well. With this being said, an obstetric clinician should be readily available, and present at the time of exploration.
Nearly 25% of trauma patients with viable fetus may have pre-term labor; and nearly 40% will experience contractions. Preterm labor in general should be treat with standard obstetric protocol. Next to maternal death, placental abruption is the next most common cause of fetal death. Non-reassuring fetal heart tones with clinical evidence concerning for placental abruption warrants emergent cesarean section. In addition to placental abruption, severe pelvic or spine fractures, fetal malposition with premature labor, maternal disseminated intravascular coagulation, and gravid uterus when interfering with exposure of potential injuries / exposure during laparotomy are all indications for emergent cesarean section. The uterus is exposed through midline vertical celiotomy. The uterus itself is incised vertically with scissor, exposing the infants head with immediate suction of the oropharynx as the infant is delivered. The umbilical cord is subsequently clamped and divided. The placenta is next manually removed with inspection of the endometrium to ensure no retained membrane present. The uterus is then closed in layers with a running absorbable stitch. Oxytocin (Pitocin) may be administered for post-partum bleeding.
- Tetanus toxoid is safe to administer in pregnancy
- Standard antibiotic prophylaxis can be used however due to teratogenic potential, aminoglycosides, quinolones, metronidazole, and sulfonamides should be avoided
- Enoxaparin or heparin may be used for inpatient pharmacologic venous-thrombo-embolic prophylaxis as it does not cross the placenta
- Further medication guidelines for treatment of the pregnant patient may be obtained at: www.cdc.gov/pregnancy/meds/treatingfortwo/index.html
- Peri-mortem cesarean delivery can be performed with fetus that is at least 25 weeks gestation, if within 15 minutes between maternal death and delivery. Maternal CPR should be continued in conjunction with ACS protocol to allow immediate neonatal support and delivery to occur within 4 minutes of maternal death.
- Emergent management of abruptio placentae
- Penetrating abdominal trauma
- Uterine rupture
- Retroperitoneal hemorrhage
- Rupture of amniotic membrane
- Amniotic fluid embolism
- Placental abruption
Pearls and Other Issues
Lastly, consideration of perimortem caesarean section should be considered if maternal death occurs and pregnancy is viable (>23 weeks). See Cesarean, Perimortem section for further information.
Enhancing Healthcare Team Outcomes
Trauma during pregnancy is a commonly encountered disease state in the emergency department. Evaluating pregnant patients has significantly more medical, social and ethical considerations than non-pregnant patients. Hence, the management of pregnancy-related trauma usually involves an interprofessional group of health professionals. Trauma is the leading cause of death among young and middle aged adults. The key is education and preperation. Pregnant females should be told to wear a seat belt while in a car and avoid intense physical activities that pose a risk for falls. If there is domestic abuse in the home, the pregnant female should be encouraged to seek a safe shelter. Follow up by a social worker is key. At every prenatal visit, the obstetric nurse should emphasize the importance of safety. (Level V)
The outcomes of pregnant women who suffer trauma depend on the type and extent of trauma. Overall, penetrating trauma carries a fetal mortality rate of 30 to 80%, but the maternal mortality rates are low as the fetus protects the underlying organs of the pelvis. After blunt trauma, the morbidity and mortality depend on the severity of the force. Various series report morbidity rates of 5 to 45% in pregnant women suffering from blunt trauma. In many series, fetal demise is high when moderate to severe hemorrhage occurs. (Level V)