congenital anomaly vs birth defect

congenital anomaly and birth defect both are nouns.

Word	Noun	Adjective	Verb	Adverb
congenital anomaly	Yes	No	No	No
birth defect	Yes	No	No	No

As nouns, congenital anomaly and birth defect are synonyms defined as:

Other synonyms of congenital anomaly include congenital abnormality, congenital defect, congenital disorder.

congenital anomaly (noun)	birth defect (noun)
a defect that is present at birth	a defect that is present at birth