Before we’ve even thought about the complexities of bringing a baby into the world, Hollywood has fed us a pretty consistent image of what childbirth looks like. Panic, primal screaming, sweat, chaos and a whole heap of pain is what we’re led to believe the delivery room looks like.

The reality is often very different, and even more so for the one in 100 women that carry the KCNG4 gene variant, which a recent study claims allows them to give birth without any anaesthetic!

The rare KCNG4 gene variant is believed to inhibit how pain is processed by the nervous system, raising pain thresholds and acting as a “natural epidural”.

Researchers from the University of Cambridge found the useful gene in the fortunate women who had been able to carry their first-born child to full term, and experienced an uncomplicated labour and vaginal delivery without requesting any pain relief.

Dr Ewan St. John Smith, senior co-author of the study from the university of Cambridge, 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 labour – to switch it on.

“This makes it less likely that pain signals can reach the brain.”

Research found that one in 100 women carry the KCNG4 gene variant which allows them to give birth without any anaesthetic.

Research participants who had birthed at Cambridge’s Addenbrooke’s Hospital were tested to see if there was a commonality to those who had birthed without requesting any pain relief.

Because if there’s something that IS known, it’s that labour and childbirth hurt. A lot. High levels of pain tolerance during this time, the researchers stated, is not the norm.

“It is unusual for women to not request gas and air, or epidural for pain relief during labour, particularly when delivering for the first time,” said Dr Michael Lee, joint first author.

The women were subjected to various tests to gauge pain threshold across a few different scenarios, which included heat and pressure as well as having their hands plunged into icy water.

The academics were not surprised to discover that the women who did not opt for pain relief in labour had a much higher pain threshold during these experiences.

This clear difference in the way that the subjects reacted to pain prompted further research, including genetic analysis of the women, which revealed a higher than normal prevalence of the KCNG4 gene variant in those with the unusual high pain threshold.

WATCH: Amazing vaginal birth video …

The KCNG4  gene plays a huge role in controlling the way the human body processes pain from one nerve to the other. Researchers believe the the protein that sends electrical signals through the body is numbed in those with this gene variant, resulting in a lessened experience of pain.

The discovery of the specific variant has possibilities that may lead to new pain-management drugs.

“This approach of studying individuals who show unexpected extremes of pain experience also may find wider application in other contexts, helping us understand how we experience pain and develop new drugs to treat it,” said Professor David Menon, senior co-author.