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22 July 2020, 12:17
A very rare gene could explain why some women don't need pain relief during childbirth.
According to a new study, some women have a gene which can reduce how much pain they feel during childbirth.
The variant acts as a natural epidural and reduces the ability of nerve cells to send pain signals to the brain, with only about one in 100 women thought to have it.
The study - conducted by Addenbrooke’s Hospital and the University of Cambridge - recruited a group of mums who had carried their first baby to full term, and who had an uncomplicated vaginal delivery without pain relief.
Their pain threshold was then tested through many experiments which included applying heat and pressure to their arms and plunging their hands into icy water.
Scientists carried out the same tests on women who had similar births, but who required pain relief.
When compared, the first group showed higher pain thresholds for heat, cold and mechanical pressure.
Their genetic code was then explored, and scientists found a rare variant to one cell that was present in many of the women who didn't need assistance during childbirth.
This gene called KCNG4 controls the electrical signal that flows along our nerve cells.
Co-author of the study, Ewan St. John Smith explained: "The genetic variant that we found in women who feel less pain during childbirth leads to a 'defect' in the formation of the switch on the nerve cells,".
"In fact, this defect acts like a natural epidural. It means it takes a much greater signal -- in other words, stronger contractions during labor -- to switch it on.
"This makes it less likely that pain signals can reach the brain."
Senior co-author Professor Frank Reimann added: “Not only have we identified a genetic variant in a new player underlying different pain sensitivities but we hope this can open avenues to the development of new drugs to manage pain.”
Their study was published in the journal Cell Reports on Tuesday.