Maternal predictors of fetal demise in trauma during pregnancy. Trauma complicates 6 to 7 per cent of all pregnancies, but fetal demise secondary to maternal trauma occurs much less frequently. This study was done to analyze the incidence of fetal demise as a function of 21 maternal characteristics determined within the first 24 hours after trauma. Nine instances of fetal demise were identified from 73 pregnant patients with trauma admitted to four Level I trauma centers from a combined data base of 30,000 patients. Maternal factors examined by logistic regression were Injury Severity Score (ISS), Trauma Score (TS), Abbreviated Injury Scale (AIS), fluid requirements in the initial 24 hours, systolic blood pressure (SBP), heart rate (HR), hemoglobin, hematocrit and arterial blood gas analysis. Fetal demise was found to be associated with increasing ISS, increasing face and abdominal AIS, increasing fluid requirements, maternal acidosis and maternal hypoxia. Standard maternal laboratory and physiologic parameters, such as hemoglobin and hematocrit, oxygen and hemoglobin saturation, partial pressure of carbon dioxide, SBP and HR were not predictive. The TS was also found to be nonpredictive. 