childbirth vs birth

childbirth and birth both are nouns.

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

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

childbirth: the parturition process in human beings; having a baby; the process of giving birth to a child
birth: the process of giving birth

Other hypernyms of childbirth include birthing, giving birth, parturition.

childbirth (noun)	birth (noun)
the parturition process in human beings; having a baby; the process of giving birth to a child	the event of being born
	a baby born; an offspring
	the process of giving birth
	the kinship relation of an offspring to the parents
	the time when something begins (especially life)

childbirth (verb)	birth (verb)
	cause to be born