This narrowing of attention, the concentration of the mind on maintaining the breathing patterns, diverts the attention from the physical pain sensations during childbirth with the result that the mother becomes less aware of any uncomfortable sensations. The power of a mind in a trance can do things which it ordinarily cannot do. Giving birth painlessly is only one example. Trance can also be used to reduce psychological pain such as anxiety, fear, worry, as well as the universal Weltschmerz. Instead of consciously addressing the causes of the pain, trance can successfully divert the attention so that one is aware of neither the pain nor the causes of pain.
Hypnotic trance is only one way to remove pain.
Alcohol, drug, religion, work, consumption, and TV trance addictions can also be counted as other ways of removing pain. I believe addictions of all sorts are forms of pathological trance. Limited awareness, tunnel vision, the special characteristic that identifies a dysfunctional, impoverished reality, also identifies a type of pathological trance state that may be also a characteristic of all addictions. If you really want to get into a pathological trance and stay there, here's a general recipe. First, you must impoverish your reality by removing all distractions and limit your awareness to a single, or at most a very few objects of attention.