Pregnancy, Trauma in

Basics

Description

  • Fetal and maternal injury after the first trimester:
    • Increased rate of fetal loss, but not maternal mortality
  • Likelihood of fetal injury increases with the severity of maternal insult
  • Physiologic hypervolemia of pregnancy may lead to an underestimation of blood loss:
    • Clinical shock may be apparent only after a 30% maternal blood loss
  • Abdominal findings are less evident in the gravid patient
  • Minor trauma can also lead to fetal injuries (at least 50% of fetal losses)
  • An Injury Severity Score (ISS) >9 is associated with a worse outcome
  • 1 in 3 pregnant women admitted to the hospital for trauma will deliver during her hospitalization
  • Less frequent bowel injury
  • More frequent retroperitoneal hemorrhage due to the engorgement of pelvic organs and veins
  • Increased morbidity and mortality with pelvic fractures due to pelvic and uterine engorgement
  • Fetal or uterine trauma includes:
    • Placental abruption
    • Fetal–maternal hemorrhage (FMH)
    • Premature labor
    • Uterine contusion or rupture
    • Fetal demise
    • Premature membrane rupture
    • Hypoxemic or anatomic fetal injury (skull fracture)
  • Abruption occurs in up to 60% of severe trauma and 1–5% of minor injuries:
    • Most common cause of isolated fetal death
    • Accounts for up to 50% of fetal loss
    • May occur with no external bleeding (20%)
    • Occurs after 16 wk of gestation
    • Can present with abdominal pain, cramping, and/or vaginal bleeding
    • Hallmark is uterine contractions
  • Uterine rupture:
    • Usually in patients with prior C-section
    • Nearly universal mortality
    • 10% maternal mortality
  • Pelvic fracture:
    • May be an independent predictor of fetal death
    • Fatal insults to fetus can occur in all trimesters
    • 10% fetal mortality in patients with minor fractures
  • FMH occurs in >30% of severe trauma:
    • Isoimmunization of Rh-negative mothers can occur with as little as 0.03 cc of FMH
  • Penetrating trauma results in direct injury to fetus, maternal shock, and premature delivery
  • Fetal mortality is 73% and maternal mortality is 66% following penetrating trauma
  • Falls and slips occur in 1 out of 4 pregnant women and may cause:
    • 4.4-fold increase in preterm birth (PTB)
    • 8-fold increase in placental abruption
    • 2.1-fold increase in fetal distress
    • 2.9-fold increase in fetal hypoxia
  • Burns: If BSA involved is >40% the maternal and fetal mortality approaches 100%
  • Intentional trauma and domestic violence (DV) increases the risk for PTB 2.7-fold and low birth weight 5.3-fold
  • Risk factors for DV include substance abuse, low socioeconomic status, unintended pregnancy, history of DV prior to pregnancy, history of witnessed violence, and unmarried status
  • Electrocution is a significant cause of fetal mortality

Etiology

  • Trauma occurs in ∼7% of all pregnancies
  • Just over half of trauma occurs in third trimester
  • Mean maternal age ∼24 yr
  • Nearly half (46.8%) of all injury hospitalizations involve woman younger than 25 yr of age
  • There is a strong inverse relationship with maternal age and incidence of trauma
  • Most common cause of nonobstetric morbidity and mortality in pregnancy
  • Rate of fetal loss 3.4–38%
  • Causes:
    • Motor vehicle accidents (MVA; 48–84%)
    • DV
    • Falls
    • Direct abdominal trauma
    • Penetrating (stab or gunshot)
    • Electrical injury or thermal burn
    • Suicide
    • Exposure to toxins
  • Higher rate in younger woman
  • Substance abuse is a common accompaniment of MVA and DV

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