birth defect vs congenital anomaly

birth defect and congenital anomaly both are nouns.

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

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

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

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