Ultrasound studies examined fetuses of depressed and nondepressed mothers. Fetuses of depressed mothers were more active during mid-gestation and exhibited lower baseline heart rate and moved less during late-term vibratory stimulation. Mid-gestation heightened activity and late-term diminished responsivity may be a prenatal manifestation of the "general adaptation syndrome." Color Doppler technology measured blood flow velocity in the middle cerebral artery of fetuses whose mothers were prescribed SSRIs or lithium. SSRIs were associated with velocity increases and lithium with velocity decreases. The effects of psychotropic medications on prenatal neurobehavioral development require further study to document potential benefits and adverse effects.