vaginal birth vs birth

vaginal birth and birth both are nouns.

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

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

vaginal birth: 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 vaginal birth include birthing, giving birth, parturition.

vaginal birth (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)

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