babyhood vs early childhood

babyhood and early childhood both are nouns.

Word	Noun	Adjective	Verb	Adverb
babyhood	Yes	No	No	No
early childhood	Yes	No	No	No

As nouns, babyhood and early childhood are synonyms defined as:

Other synonyms of babyhood include infancy.

babyhood (noun)	early childhood (noun)
the earliest state of immaturity	the early stage of growth or development
the early stage of growth or development