Our body is an amazing system. Inbuilt into this system are a couple of known mechanisms that can allow our bodies to naturally deal with how we interpret pain. These include:
Endorphin release
The gate control theory
Endorphin release
Endorphins (or 'endogenous opiates') were first discovered in 1975. They are natural opiate-like substances, similar to morphine and heroin, but not as potent. Endorphins are manufactured by our bodies in the presence of pain and act as a natural analgesic. There is some evidence to suggest that the pregnant woman's body starts to produce more endorphins just prior to labour. Endorphins are released by the ends of the 'descending nerve fibres' or 'going down' fibres that come down the spinal cord from the brain.
When we feel a certain level of pain, the descending nerve fibres release endorphins at the level of the spinal cord, where they meet the sensory nerves carrying the 'pain messages' from our body. This local release of endorphins by the nerves inhibits some or all of the pain messages going up to the brain.
For many women, endorphins will also positively alter the memory of their birth experience and in some cases induce an amnesic effect (forgetting the pain). Endorphins can therefore have the potential to strengthen the woman's psyche and provide an internal 'protection' against the intensity of labour and giving birth.
The gate control theory
The 'Gate Control Theory' was first proposed by Melzack and Wall in 1965. They have since refined their theory (in 1988) and it remains one of the most respected understandings of one way our bodies can diminish the perception of pain.
The Gate Control Theory, is based on the fact that when the larger A - b (beta) skin nerves (that sense touch, heat, cold and pressure) are stimulated, they are capable of overriding the smaller A - d (delta) and C nerve fibres that sense the sharp, burning or aching pains.