With the active life-style of today's pregnant women, the effects of trauma have become an important obstetric concern. A protocol was developed to monitor pregnancies complicated by major blunt abdominal trauma in the third trimester, looking specifically for delayed placental and/or fetal problems. Of the 84 pregnancies studied, the most serious complication was placental abruption. Although abruption occurred in only two cases, one case was associated with a ruptured uterus and fetal death. There were no cases of delayed abruption or delayed fetal compromise. The most common complication was preterm labor, occurring in 28% of cases when the traumatic insult happened before 37 weeks' gestation. Of these 17 patients, 15 were successfully treated with tocolysis. There were no cases of direct fetal injury or Rh-isoimmunization. A revised protocol is recommended for limited outpatient observation with nonstress testing and screening ultrasonography to rule out preterm labor and placental abruption and to document fetal well-being.