INTRODUCTION AND EPIDEMIOLOGY
Trauma is the leading cause of non–obstetric-related morbidity and mortality in pregnant women.1,2 Seven percent of all pregnant women will experience a traumatic injury, of whom 0.4% will require admission.3 Blunt trauma is more common than penetrating trauma. Motor vehicle crashes, falls, and assaults compose the major causes of blunt trauma during pregnancy.2,4
Motor vehicle crashes account for 50% of pregnancy-related trauma, and placental abruption can occur even with low-speed deceleration crashes.3,5 The best predictors of fetal loss or other adverse outcomes are crash severity and lack or improper use of seat belts.6 Pregnant women should be advised to use both seat belts and air bags.7 For proper fit, the lap belt should be worn under the gravid uterus (i.e., across both anterior superior iliac spines and the pubic symphysis) with the shoulder harness positioned snugly between the breasts and off to the side of the uterus.7 Combined with proper body positioning (i.e., mother seated 10 inches from the dash and steering column) and seat belt placement, the benefits of air bags appear to outweigh the risks.7,8
Falls occur most frequently during the second and third trimesters. This risk is likely due to weight gain affecting balance and coordination. Twenty-seven percent of women fall at least once during pregnancy; the vast majority occur indoors and/or on stairs.9
One in three women are raped, physical assaulted, and/or stalked by an intimate partner in their lifetime.10 Studies have shown that 3% to 9% of pregnant woman are abused during their pregnancy.11,12 Consider intimate partner violence in all cases of trauma and use screening tools.10,13 Provide social services consultation or referral if there is concern for the mother’s safety.1
Trauma during pregnancy is associated with several complications, including preterm labor, premature rupture of membranes, placental abruption, fetal maternal hemorrhage, uterine rupture, cesarean section, and pregnancy loss. Placental abruption is second only to maternal death as the most common cause of fetal death. Placental abruption may also lead to the introduction of placental products into the maternal circulation, stimulating disseminated intravascular coagulation or amniotic fluid embolism. Even minor maternal injuries have been associated with placental abruption and sudden fetal demise.5
A fetus is considered viable at 22 to 24 weeks of gestation or a weight of 500 grams. Achieving successful outcomes for both mother and fetus requires a collaborative effort by the prehospital, ED, trauma, obstetrics, and neonatology (neonatal intensive care unit) teams. The emergency physician should be well-versed in the care of the pregnant patient as this will enhance her care in the setting of trauma. Fetal survival is dependent on maternal survival. Therefore, resuscitation of the mother always takes priority.
ANATOMIC AND PHYSIOLOGIC CHANGES OF PREGNANCY