Fetal ethology means fetal activity and behavioral states in the uterine environment. Behavioral states may be defined by various measurable physiological variables, such as heart and respiratory rates, eye movements, body tone and body movements. Fetal motor behavior provides information about the early stages of the neurodevelopmental process. Movement was the first aspect of fetal behavior, the clinical significance of which became was recognized. Fetal behavior provides an opportunity for studying motor, sensory and cognitive functions in the fetus. Behavior can be utilized to study the immediate well-being of the fetus. The latter can be compromised as a result of a number of pathological factors. In high risk pregnancies, the study of fetal behavior may help the clinician to establish the optimum time for the delivery.