family planning vs birth prevention

family planning and birth prevention both are nouns.

Word	Noun	Adjective	Verb	Adverb
family planning	Yes	No	No	No
birth prevention	Yes	No	No	No

As nouns, family planning and birth prevention are synonyms defined as:

family planning and birth prevention: limiting the number of children born

Other synonyms of family planning include birth control.

family planning (noun)	birth prevention (noun)
limiting the number of children born	limiting the number of children born