The RCOG has on two previous occasions reviewed the evidence surrounding fetal awareness. A Working Party report in 1997 was followed by extensive review of the scientific and clinical practice relevant to the issue, with a second report published in 2010. That report concluded that the cortex is necessary for pain perception, that connections from the periphery to the cortex are not intact before 24 weeks of gestation, and it is therefore reasonable to conclude that a fetus cannot experience pain in any sense prior to this gestation.
Since 2010, there have been considerable developments in in-utero surgery, and in the neuroscientific study of pain perception. In the light of these ongoing scientific developments, the RCOG agreed it would be timely to review the 2010 Working Party report.
An expert group was convened to review the literature since 2010 and assess whether developments in the understanding of fetal awareness and pain might impact clinical practice. The report sets out the findings and recommendations of the group.
The RCOG is currently considering how to create a version of the report for lay readers.
Key findings and recommendations
- Pain research to date indicates that the perception of pain requires a comprehensive network of neural connections in the brain rather than the presence or absence of a specific region or set of connections.
- Advances in neuroimaging have revealed the maturation of fetal brain resting state networks, which consist largely of local patterns of connectivity from approximately 28 weeks of gestation, with long range functional connectivity emerging and gradually increasing after 30 weeks of gestation.
- Advances in ultrasound imaging and dynamic MRI have increased the quality of recordings of fetal behaviour. While these early movements are spontaneously generated and do not require a sensory stimulus to trigger them, distinct reflex responses to innocuous sensory stimuli, such as auditory events, can be measured at 28 weeks of gestation, as spontaneous movements decline.
- A measurable difference between the facial responses to a noxious and an innocuous stimulation is first seen from approximately 33 weeks of gestation. At the same stage, brain activity distinguishes between the two types of stimulation.