By 10 weeks, the palms of the hands are sensitive to touch, and
at 11 weeks the face and extremities likewise respond to tactile
stimuli. By 13.5 weeks, these responses are sufficiently
elaborate and sufficiently avoidant to warrant the definite
conclusion that the foetus responds aversively, not reflexively.
They evidence an integrated physiological attempt to escape
noxious stimuli. In response to experiments performed on 12 to
16 week foetuses, movements of the head, body and limbs have
been observed. These movements were vigorous, and consisted of
ventro - or dorsoflexion of the trunk, flexion of the limbs, and
turning of the head, indicating the presence of acute foetal
pain. It is agreed that a foetus must be heavily sedated before
intrauterine manipulation, such as transfusions, because such
painful stimuli cause the foetus to move, making the procedure
difficult. In the sixth to seventh weeks, nerves and muscles
work together for the first time. If the area of the lips, the
first to become sensitive t