childbed vs lying-in

childbed and lying-in both are nouns.

Word	Noun	Adjective	Verb	Adverb
childbed	Yes	No	No	No
lying-in	Yes	No	No	No

As nouns, childbed and lying-in are synonyms defined as:

childbed and lying-in: concluding state of pregnancy; from the onset of contractions to the birth of a child

Other synonyms of childbed include confinement, labor, labour, parturiency, travail.

childbed (noun)	lying-in (noun)
concluding state of pregnancy; from the onset of contractions to the birth of a child	concluding state of pregnancy; from the onset of contractions to the birth of a child