Minor maternal trauma can be deadly for fetus.(Obstetrics)

KAILUA KONA, HAWAII -- Insignificant trauma to the mother may not be insignificant to the fetus, Dr. William G. Barsan said at a conference on obstetrics, gynecology, perinatal medicine, neonatology, and the law.

Severe maternal injury is likely to lead to fetal loss in 40%-50% of cases, but severe maternal injuries are relatively rare. Minor injuries to the mother result from 88% of trauma in pregnancy; 60%-70% of fetal losses resulting from maternal trauma follow relatively minor maternal injuries, said Dr. Barsan, professor and chair of emergency medicine at the University of Michigan, Ann Arbor.

Placental abruption is the cause of fetal death in 50%-70% of losses after maternal trauma. "This is the one that may occur with relatively minor trauma" and can be hard to detect, he said.

In one study of nine fetal deaths after 25-mph motor vehicle crashes in which the mothers were not wearing seat belts, six of the women sustained only "insignificant" injures, such as bruising or abrasions, Dr. Barsan noted.

A separate study of 22 fetal deaths resulting from motor vehicle crashes found that six mothers sustained no injuries at all, and nine had bruised abdomens. Other maternal injuries included three ruptured uteri, two chest injuries, one extremity fracture, and one head injury with shock.

Perform electronic fetal monitoring for 4 hours on any pregnant woman with a viable fetus who sustains a significant impact to the torso from falling, crashing, or other causes, Dr. Barsan advised. In one study, all patients with placental abruption after trauma developed uterine contractions every 2-5 minutes at some point during a 4-hour monitoring period.

Many women will have uterine contractions after trauma, and most will not have placental abruption. At Dr. Barsan's institution, women with frequent uterine contractions after trauma receive an additional 24 hours of electronic fetal ...