premature labor vs childbed

premature labor and childbed both are nouns.

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

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

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

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

premature labor (noun)	childbed (noun)
labor beginning prior to the 37th week of gestation	concluding state of pregnancy; from the onset of contractions to the birth of a child