Nonstress testing of the fetal heart rate is an antepartum test for fetal well-being utilizing the fetal heart rate response to fetal movement. Performing the test during times of maximum fetal movement should reduce the time required for the test. In this study, fetal activity was evaluated before and during a 3-hour glucose tolerance test to determine the effect of maternal blood glucose levels on fetal activity. Fetal activity was monitored by a nurse at the bedside throughout the study, utilizing both the patient's perception of fetal movement and the recording of fetal movement by the tokodynamometer. Fetal activity increased significantly during the first 30 minutes after maternal ingestion of 100 g glucose and was significantly greater during the last 10 minutes of this time interval. No correlation could be found between absolute levels of glucose at any measured level and fetal activity.