premature labor vs confinement

premature labor and confinement both are nouns.

Word	Noun	Adjective	Verb	Adverb
premature labor	Yes	No	No	No
confinement	Yes	No	No	No

As nouns, confinement is a hypernym of premature labor; that is, confinement is a word with a broader meaning than premature labor:

premature labor: labor beginning prior to the 37th week of gestation
confinement: concluding state of pregnancy; from the onset of contractions to the birth of a child

Other hypernyms of premature labor include childbed, labor, labour, lying-in, parturiency, travail.

premature labor (noun)	confinement (noun)
labor beginning prior to the 37th week of gestation	the act of restraining of a person's liberty by confining them
	the act of keeping something within specified bounds (by force if necessary)
	the state of being confined
	concluding state of pregnancy; from the onset of contractions to the birth of a child