Abstract
One of the central issues in developmental neurology is the need to formulate concepts helping to understand human behavior, which reflects the central nervous system from early intrauterine age to the young infant and even up to adulthood. Real-time ultrasound observations have been used from the early 1980s onwards to witness the origin, occurrence and developmental course of specific fetal movement patterns emerging during early prenatal life. A large variety of movement patterns has been observed: startles; general movements; breathing movements; head, trunk and extremity movements; jaw openings; yawning; sucking; swallowing; hiccups; and hand/face contacts. In combination with fetal heart rate monitoring, two-dimensional ultrasound has been used in the third trimester to document the development of fetal behavioral states continuing from pre- to postnatal life. In the early 1990s we started to perform longitudinal examinations in twin pregnancies observing similar movement patterns to those in singletons. In multiple pregnancies, the inter-twin variance of different subsets and the possible impact of internal and external parameters can be studied. In addition, we have studied inter-twin reactions towards touch, reflecting the development of both initiative and sensitivity towards touch and finally the first inter-human contacts. Here we describe some essential issues of the documentation of fetal behavior in singleton and twin pregnancy.