"In contrast to the endocrine and haemodynamic responses to a noxious stimulus, which are easily quantified, it has not been possible to directly measure the cortical response to such a stimulus. Assessments about the gestation at which a fetus could feel pain are therefore made on the basis of the existence of the necessary neural pathways for pain perception, particularly the nature of thalamocortical connections (see section 2), as well as indirect evidence for functionality based on evoked responses and evidence for a sleep–wake cycle of EEG activity. Interpretation of existing data indicates that cortical processing of pain perception, and therefore the ability of the fetus to feel pain, cannot occur before 24 weeks of gestation and that the nature of cortical activity becomes more complex as gestation advances from this point. It is reasonable to infer from this that the fetus does not require analgesia for interventions occurring before 24 weeks of gestation. Furthermore, and importantly, the evidence that analgesia confers any benefit on the fetus at any gestation is lacking."