The purpose of this study was to determine if there is a relationship between fetal behavior and maternal anxiety during pregnancy. The study population consisted of 18 uncomplicated human pregnancies at 38 to 40 weeks gestation. Maternal anxiety was assessed one time using Spielberger's State-Trait Anxiety Inventory. After an overnight fast, each mother was given a standard meal on arrival to the fetal testing unit. Each fetus was examined for 4 hours using heart rate monitoring and real-time sonography. Fetal behavioral states were assigned based on heart rate pattern and the presence or absence of eye and gross body movements. We found that, compared with fetuses of mothers with low trait anxiety scores, fetuses of mothers with relatively high trait anxiety scores spent significantly more time in quiet sleep and exhibited less gross body movement when in active sleep. The results of this pilot study raise the possibility that maternal anxiety during pregnancy may have a significant effect on fetal behavior.