CABO SAN LUCAS, MEXICO — Abdominal trauma during pregnancy endangers the woman and her fetus, but avoiding some common clinical errors in managing such patients can reduce these risks, according to John A. Marx, M.D.
Abdominal trauma during pregnancy is “a huge concern and underrated,” said Dr. Marx, chairman of emergency medicine at Carolinas Medical Center, Charlotte, N.C.
Abdominal trauma occurs in 1%–12% of all pregnancies and leads to hospitalization in 0.4% of such cases, he said at a conference on obstetrics, gynecology, perinatal medicine, neonatology, and the law.
Trauma that causes a pelvic fracture leads to maternal death in 9% of cases and fetal death in 38% of cases. Placental abruption—seen in 2%–4% of women who suffer minor abdominal trauma and half of women with life-threatening abdominal trauma—results in fetal death 50%–70% of the time.
Be prepared to recognize shock early and treat it aggressively in pregnant women with abdominal trauma.
Don't rely too much on a nontender abdomen as a sign that everything is okay after abdominal trauma during pregnancy.
Dr. Marx outlined other mistakes to avoid:
▸ Failure to teach proper seat belt use. Motor vehicle accidents cause 70% of all cases of abdominal trauma in pregnancy. Compared with a belted passenger, an unbelted pregnant woman in a car crash has double the risk of vaginal bleeding and quadruple the risk of fetal death.
Advise women to place their lap belt below the uterus and across the hips and place the shoulder belt between the breasts and to the side of the abdomen. Placing the seatbelt improperly across the abdomen increases force on the uterus three- to fourfold, compared with proper seat belt use.
Air bags do protect pregnant passengers, he added. “There's a great deal of misunderstanding about this,” Dr. Marx said.
▸ Failure to order needed radiologic studies. This failure is frequently due to concern about radiating the fetus and represents “a huge error in trauma management,” he said. A dose of 5 rad or less is considered an acceptable cumulative fetal exposure. X-rays that deliver less than half a rad each include films of the anterior-posterior pelvis, lumbosacral spine, thoracic spine, and periapical or lateral views. A CT scan of the abdomen delivers 2.6 rads to the fetus, and a CT of the abdomen and pelvis delivers 3–9 rads, although helical CT decreases radiation exposure by 14%–30%. “You can still do these studies, but you can't do a bunch of them,” he said.
▸ Failure to obtain coagulation studies. The risk of disseminated intravascular coagulation increases during pregnancy.
▸ Overreliance on ultrasound to detect placental abruption. Cardiotocographic monitoring is much more sensitive, though less specific, than ultrasound in diagnosing placental abruption. All women with pregnancies of 24 weeks or greater who sustain blunt trauma to the abdomen should undergo cardiotocographic monitoring, which consists of continuous Doppler monitoring of fetal cardiac activity and electronic recording of uterine activity.
Placental abruption with a 50% tear can quadruple the risk of stillbirth, and a 75% tear increases the risk of stillbirth 39-fold.
▸ Failure to monitor the fetus for 4–24 hours. Four hours is sufficient if the trauma carries low risk, the mother is asymptomatic for placental abruption, and cardiotocographic monitoring results are normal. If the trauma affected a major bodily mechanism, the mother is symptomatic, or monitoring results are abnormal within the first 4 hours, monitor for at least 24 hours.
▸ Failure to avoid supine hypotensive syndrome. “This is another oft-missed and easy-to-treat condition,” he said. Tilting the woman's prone body up and to the left by 15–30 degrees frees the inferior vena cava from pressure from the uterus, which could otherwise cause a significant drop in systolic blood pressure.
▸ Failure to consider domestic violence. The woman's abdomen is the prime site of injury arising from domestic violence during pregnancy. If domestic violence happens once during pregnancy, there's a 60% chance it will happen again. Only 3% of pregnant women who seek care for domestic violence injuries reveal the true cause to physicians.
▸ Failure to perform a perimortem cesarean section promptly. When the woman is dead or moribund but the fetus is viable, performing a C-section within 5 minutes leads to excellent fetal outcomes. Only about 5% of fetuses survive if delivery is delayed at least 15 minutes, and most will have poor neurologic outcomes, Dr. Marx said.