alternative birth vs childbirth

alternative birth and childbirth both are nouns.

Word	Noun	Adjective	Verb	Adverb
alternative birth	Yes	No	No	No
childbirth	Yes	No	No	No

As nouns, childbirth is a hypernym of alternative birth; that is, childbirth is a word with a broader meaning than alternative birth:

alternative birth: a method of childbirth that avoids intrusive high-tech medicine in favor of more natural and homely settings
childbirth: the parturition process in human beings; having a baby; the process of giving birth to a child

Other hypernyms of alternative birth include accouchement, childbearing, vaginal birth.

alternative birth (noun)	childbirth (noun)
a method of childbirth that avoids intrusive high-tech medicine in favor of more natural and homely settings	the parturition process in human beings; having a baby; the process of giving birth to a child