SELECTED PATIENT POPULATIONS

Trauma and Pregnancy (also see Chapter 58 )

Trauma to pregnant patients is associated with a high risk of spontaneous abortion, preterm labor, or premature delivery, depending on the location and magnitude of the mother's injury. Early consultation with an obstetrician is desirable for any pregnant trauma patient, both for immediate management and for long-term follow-up. The best treatment of the developing fetus consists of rapid and complete resuscitation of the mother. Trauma patients in the first trimester of gestation may not realize that they are pregnant; for this reason, human chorionic gonadotropin testing is part of the initial laboratory studies for any injured woman of childbearing age. Serious trauma occurring during the period of fetal organogenesis may induce birth defects or miscarriage as a result of hemorrhagic shock with uterine ischemia, radiation to the pelvis, or the effects of medications. Indicated radiologic tests should not be deferred, but shielding of the pelvis should be provided whenever possible. Patients who do not spontaneously miscarry should be advised of the potential risks related to trauma and anesthesia and be referred for counseling if desired. Dilatation plus curettage of the uterus is advisable after miscarriage to avoid toxicity arising from retained products of conception.^[210]

Trauma occurring in the second or third trimester of pregnancy necessitates early ultrasonographic examination to determine fetal age, size, and viability. Monitoring of the fetal heart rate is indicated if the pregnancy is sufficiently far advanced that the fetus would be viable if delivered. Preterm labor is very common in this population and should be treated with β-agonists or magnesium at the direction of the obstetrician; delivery should be delayed as long as the fetus is not an unacceptable metabolic stress on the mother. Delivery by cesarean section is indicated if the mother is in extremis, if the uterus itself is hemorrhaging, or if the gravid uterus is impairing surgical control of abdominal or pelvic hemorrhage. ^[211] Placental abruption can occur in response to substance abuse or abdominal trauma and can precipitate life-threatening uterine hemorrhage. Emergency cesarean section is indicated. The Kleihauer-Betke blood test can be used to determine whether fetal blood has leaked into the maternal circulation ^[212] ; if the test is positive, anti-Rh₀ immune globulin administration is recommended for any Rh-negative mother carrying an Rh-positive fetus. By the third trimester, the uterus is sufficiently enlarged to compress the inferior vena cava and impair venous return to the heart when the patient is positioned supine and thus contribute to hypotension. Left lateral uterine displacement is indicated to treat this problem. If the patient is immobilized on a long spine board because of concern for thoracic or lumbar spinal fracture, the whole board can be tipped to the left.