birth vs childbirth

birth and childbirth both are nouns.

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

As nouns, childbirth is a hyponym of birth; that is, childbirth is a word with a more specific, narrower meaning than birth:

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

birth (noun)	childbirth (noun)
the event of being born	the parturition process in human beings; having a baby; the process of giving birth to a child
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)

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