Late meconium passage in labor--a sign of fetal distress?

Although the passage early in labor of thick amniotic fluid heavily stained with meconium is recognized as an indication of potential fetal asphyxia, the significance of late passage of meconium-stained fluid in labor is less certain. One hundren twenty-eight patients with late passage of meconium in labor and 134 control patients were examined, using chi 2 and discriminant analysis, to determine if any relationships existed between fetal heart rate (FHR) patterns, late passage of meconium in labor, and neonatal morbidity. In the group with late meconium passage, adequate baseline FHR variability and nonperiodic accelerations were predictive of high Apgar scores, and repeated (over 20) variable decelerations were predictive of low Apgar scores. In the control group, none of the FHR patterns examined were predictive of Apgar score. Thus, the combination of late passage of meconium in labor with other intrapartum signs may indicate a fetus at risk for asphyxia when neither sign alone is predictive. The presence of late meconium passage demands close observation of the patient in labor, including assessment by electronic FHR monitoring.