Foetal pain and anaesthesia during prenatal surgery

Abstract

Objectives: Foetal surgery is a relatively new branch of medicine; the health providers involved are currently wondering what kind of anaesthesia should be provided to the foetuses. In the last few years, new advances have been reported on foetal sensoriality and capability for feeling pain; meanwhile alerts have been issued on the risks of prolonged anaesthesia in the early infancy. Aim of this paper is reviewing the main data on foetal pain, to be aware of which is the time in pregnancy when it is likely to be felt. The secondary aim is to point out which are the anaesthetics and analgesics appropriate for prenatal surgery. Mechanism: A review of the literature published in the last 20 years in the field of fetal sensoriality and fetal sergery has been carried out; the most pertinent papers have been retrieved, and their conclusions are here summarized and analysed. Findings in brief: Pain can be felt by the human fetus in the second half of pregnancy: data of physiological and behavioural studies show it with increasing evidence, as long as the gestational age increases. With regard to the best anaesthesia in this case, it seems that the mere anaesthetics given to the mother, though apparently sufficient during laparoscopic surgery, are not sufficient to anesthetize the foetus during open surgery; here some references are given for the best and safest foetal direct analgesic treatment. Conclusions: Surgeons should approach carefully fetal surgery, according with the latest findings in this field.

The fetal pain paradox

“…Implications of fetal pain perception at earlier gestational ages include the need for research in fetal pain assessment and management strategies to ensure adequate procedural and post-procedural pain control ( 3 , 57 , 58 ) and to prevent adverse short- and long-term sequelae, including the potential for preterm labor ( 1 , 18 ). An ethical obligation also exists to prevent, mitigate, and treat pain whenever it can be anticipated.…”

“…The study concluded that fetuses demonstrate discriminative facial expressions of acute pain following intramuscular injection ( Figures 7 , 8 ) ( 16 , 58 ). Researchers emphasized the need for continuous monitoring of fetal activity and responses to invasive fetal procedures to better assess and treat procedural and post-procedural pain ( 3 ).…”

“…First, according to the hypothesis of cortical necessity, functional thalamocortical projections to the somatosensory cortex that develop after 24–28 weeks gestation are required before conscious pain perception is possible ( 1 , 2 ). Second, the subplate modulation hypothesis holds that functional activity in the cortical subplate and/or subcortical structures is sufficient to mediate pain perception in the fetus before 24 weeks gestation ( 3 ), and possibly as early as 12 weeks gestation ( 4 ). The subplate, a transient layer located beneath the cortical plate in the developing cortex, forms the predominant cortical circuitry from the first through third trimesters ( 5 ).…”