On the feasibility of accessing acute pain-related facial expressions in the human fetus and its potential implications: a case report.

Introduction: Although pain facial assessment is routinely performed in term and preterm newborns by the use of facial expression-based tools such as the Neonatal Facial Coding System, the assessment of pain during the intrauterine life has not been extensively explored.

Objective: Describe for the first time, an experimental model to assess and quantify responses due to acute pain in fetuses undergoing anaesthesia for intrauterine surgery recorded by high-resolution 4D ultrasound machines.

Methods/results-case Report: A 33-year-old pregnant woman had congenital left diaphragmatic hernia of poor prognosis diagnosed, and her fetus was treated by fetoscopic endotracheal occlusion. Later, during the removal of the fetal endotracheal balloon by ultrasound-guided puncture, we have recorded facial expressions of the foetus before and after the anaesthetic puncture by the use of 4D ultrasound recordings, which were presented to 3 blinded coders instructed to use the Neonatal Facial Coding System for acute pain facial coding. The procedure was safe and feasible.

Conclusion: This is the first description of a recordable acute pain model in the human fetus by the use of a facial expression-based tool. The possibility to assess pain-related intrauterine behaviours would allow not only for the monitoring of the efficacy of anaesthetic procedures in the fetus but would also open the way to explore the evolution of pain-related facial responses during the fetal neurodevelopment. This method may pave the way for objective assessments of pain in fetuses, should it endure the steps of formal validation studies.