The antenatal development of fetal behavioral patterns assessed by four-dimensional sonography.

The investigation of fetal intrauterine activities has been enabled by the development of two-dimensional ultrasound. It has been shown that the earliest signs of fetal motor activity can be in the late embryonic period, and that the characteristics of fetal motor patterns change constantly throughout gestation. During the first trimester of pregnancy, the repertoire and frequency fetal movement patterns constantly expand, whereas the second and third trimesters are characterized by the progressive organization of fetal activities into complex and clearly distinct behavioral patterns. The comparison of real time ultrasonic studies of fetal behavior with the morphological studies of fetal brains has revealed that the appearance of new behavioral patterns or the transition of existing patterns directly reflect the complex neurodevelopment processes. It has been suggested that the assessment of fetal behavioral patterns could give us insight into the integrity of fetal central nervous system and enable the early detection of cerebral dysfunctions. The development of a new ultrasonic technique, four dimensional sonography, could represent a significant improvement in the assessment of fetal behavior. According to the preliminary results, this new technique could open a new perspective for the investigations of fetal behavioral patterns and contribute significantly to our better understanding of complex neurodevelopmental events. The most important neurodevelopmental events, the basic technology of 4D ultrasound and its application in the assessment of functional development of fetal central nervous system will be the subject of this review.