menorrhea vs menstrual blood

menorrhea and menstrual blood both are nouns.

Word	Noun	Adjective	Verb	Adverb
menorrhea	Yes	No	No	No
menstrual blood	Yes	No	No	No

As nouns, menorrhea and menstrual blood are synonyms defined as:

menorrhea and menstrual blood: flow of blood from the uterus; occurs at roughly monthly intervals during a woman's reproductive years

Other synonyms of menorrhea include menstrual flow.

menorrhea (noun)	menstrual blood (noun)
flow of blood from the uterus; occurs at roughly monthly intervals during a woman's reproductive years	flow of blood from the uterus; occurs at roughly monthly intervals during a woman's reproductive years