Chapter 37: Trauma in Pregnancy

INTRODUCTION

The incidence of trauma related injuries during pregnancy has increased dramatically over the past 25 years¹ and is now the leading cause of nonobstetrical maternal death in the United States.² Adverse fetal outcomes include preterm delivery, low birthweight, and fetal demise.³

The severity of trauma does not always predict the severity of injury to mother and fetus, but major trauma is associated with a 40–50% risk of fetal death.⁴ Minor trauma, encompassing lower energy mechanisms, occurs much more frequently but still carries significant risk to the fetus. A Tennessee study identified 5352 expectant mothers and classified their injuries as major if hospital admission was required or minor if only emergency room evaluation occurred.⁴ They found that women in their first or second trimester with minor injury were 1.19 times more likely to have a child with prematurity or low birth weight.

EPIDEMIOLOGY

Trauma complicates an estimated 1 in 12 pregnancies,¹ and 0.4% of pregnant women require hospitalization for their injuries.⁵ Motor vehicle crashes account for 50% of all traumatic injuries during pregnancy and 82% of trauma-related fetal deaths.⁶ A major risk factor is improper use of a seatbelt.⁷ Correct placement has the lap belt underneath the abdominal dome, decreasing the pressure transmitted across the uterus in a motor vehicle crash. The shoulder harness should overly the clavicle and run between the breasts. Sadly, this information is often overlooked during prenatal counseling.

Pregnancy makes women more prone to falls due to inherent changes such as increased joint laxity, weight gain, and dynamic postural stability.⁸ It is estimated that 1 in 4 will fall at least once during their pregnancy.⁹ Schiff found that 79% of pregnant women hospitalized after a fall were in their third trimester, and the most common injury was fracture in a lower extremity.¹⁰ The study also showed an 8-fold increase in placental abruption, a 4.4-fold increase in preterm labor, a 2.1-fold increase in fetal distress, and a 2.9-fold increase in fetal hypoxia.

Literature on thermal injuries and pregnancy is limited to case reports and series. Extensive burns cause significant physiologic stress, putting both the mother and fetus at risk. It is estimated that once the total body surface area of a burn exceeds 40%, the risk of mortality for the mother and fetus approaches 100%.¹¹

Intentional trauma is divided into two categories including assault by another person and self-inflicted injuries. Intimate partner violence (IPV) is the most common form of intentional trauma and carries significant risk to both the mother and fetus. The risk of preterm birth nearly triples and low birth weight increases 5.3-fold with such trauma.¹² The prevalence of domestic violence involving pregnant women that results in serious injury has been estimated between 10 and 30%.¹³ Risk factors associated with IPV include ...