labor vs undergo

labor is a noun but undergo is not a noun.

Word	Noun	Adjective	Verb	Adverb
labor	Yes	No	Yes	No
undergo	No	No	Yes	No

As verbs, undergo is a hypernym of labor; that is, undergo is a word with a broader meaning than labor:

labor (noun)	undergo (noun)
productive work (especially physical work done for wages)
any piece of work that is undertaken or attempted
a social class comprising those who do manual labor or work for wages
an organized attempt by workers to improve their status by united action (particularly via labor unions) or the leaders of this movement
concluding state of pregnancy; from the onset of contractions to the birth of a child

labor (verb)	undergo (verb)
undergo the efforts of childbirth	go through
work hard
strive and make an effort to reach a goal