Substance P is intimately involved with pain, anxiety, and poor mood. Substance P is the main way your body processes pain and intense stress. Under routine stress, your body simply turns up the volume knob on nerve activity and energy production and when the stress is over, everything is supposed to recover. Substance P is not used as a basic coping mechanism for low-grade stress. However, extra substance P kicks in when stress or pain is more intense, such as during the birth of your child.

If you have a good history with mood and stress management, a lack of previous traumas and pain, if you are fit entering pregnancy, if ...