The biophysical profile integrates several observations of fetal status into an assessment tool that usually is used during the antepartum period to guide clinical management. Using the standardized Manning technique, biophysical profile scores of eight or higher have been associated with decreases in perinatal mortality and incidence of cerebral palsy. During labor, abnormalities in fetal heart rate monitoring are associated with increased risk of cesarean delivery, but the rate of false positives is from 63 to 99.8 percent. Kim and colleagues studied the role of biophysical profile as an adjunct to fetal heart rate monitoring during labor to improve prediction of operative delivery and other adverse outcomes.
The authors studied 100 normal term singleton deliveries at an inner-city teaching hospital. Mothers with any medical or obstetric complications were excluded from the study. All mothers received one biophysical profile during active labor in addition to continuous fetal heart rate monitoring. The clinicians managing the labor were not aware of the biophysical profile results, and the researcher measuring the results was not aware of the fetal heart rate tracings. The biophysical profile results were correlated with cesarean delivery and admission to neonatal intensive care.
One half of the mothers studied were black, and 35 were Hispanic. Eighty-four percent of biophysical profile assessments were made at a cervical dilation of 4 to 6 cm. Scores of eight or more were recorded for 73 mothers, 16 mothers had a score of six, seven mothers scored four, and five mothers scored two. Low biophysical profile scores (six or lower) were more common in younger women of lower parity. The score was not influenced by use of epidural anesthesia, oxytocic agents, or prostaglandins. In 77 mothers, delivery was spontaneous vaginal birth. Eight mothers had instrumental deliveries, and 15 underwent cesarean delivery. The biophysical profile score was inversely related to the risk of cesarean delivery. In women with scores of two or less, the chance of cesarean delivery reached 60 percent. The relative risk of cesarean delivery rose to 8.0 in mothers with biophysical profile scores of six or less during labor.
The authors conclude that the biophysical profile could be a clinically useful tool to assess fetal status during labor and could assist in predicting which mothers are at high risk of cesarean delivery.