Women who don’t need an epidural during childbirth might be carriers of a rare genetic variant that gives them a much higher threshold for pain, scientists have discovered.
Only about one in 100 women have the variant, which reduces the ability of nerve cells to send pain signals to the brain, researchers at the University of Cambridge found.
The gene then acts as a natural epidural, it and may explain why childbirth is a less painful experience for a small number of women. Scientists put a group of women, all of whom gave birth without requesting pain relief, through a number of exercises to test their resistance to discomfort, including applying heat and pressure to their arms and asking them to plunge their hands into icy water.
When compared to another group of mothers who did require pain relief, they were shown to have a far higher threshold before they experienced pain.
It is unusual for women to not request gas and air, or epidural for pain relief during labor, particularly when delivering for the first time,” said Dr. Michael Lee, joint lead author, in a press release. “When we tested these women, it was clear their pain threshold was generally much higher than it was for other women,” said Lee, a lecturer with the University of Cambridge’s division of anaesthesia.
Their genetic code was then explored — and scientists found a unique variant to one cell that was present in many of the women who didn’t need assistance during childbirth.