The human fetus moves throughout its entire development.<unk>  refers to motion of a fetus caused by its own muscle activity. Locomotor activity begins during the late embryological stage and changes in nature throughout development. Muscles begin to move as soon as they are innervated. These first<unk> s are not reflexive, but arise from self-generated nerve impulses originating in the spinal cord. As the nervous system matures, muscles can move in response to stimuli. Generally speaking, fetal motility can be classified as either elicited or spontaneous, and spontaneous<unk> s may be triggered by either the spine or the brain. Whether a<unk>  is supraspinally determined can be inferred by comparison to<unk> s of an anencephalic fetus. This article primarily deals with voluntary and reflex<unk> s. Ages are given as age from fertilization rather than as gestational age. Some sources contend that there is no voluntary<unk>  until after birth. Other sources say that purposive<unk>  begins months earlier. 3D ultrasound has been used to create motion pictures of<unk> , which are called "4D ultrasound".
Fetal movement
Fetal circulation
Fetal distress
Placental expulsion
Amniotic fluid index
Fetal viability
Prolonged labor
Fetal-maternal haemorrhage