obstetrics vs medical specialty

obstetrics and medical specialty both are nouns.

Word	Noun	Adjective	Verb	Adverb
obstetrics	Yes	No	No	No
medical specialty	Yes	No	No	No

As nouns, medical specialty is a hypernym of obstetrics; that is, medical specialty is a word with a broader meaning than obstetrics:

obstetrics: the branch of medicine dealing with childbirth and care of the mother
medical specialty: the branches of medical science that deal with nonsurgical techniques

Other hypernyms of obstetrics include medicine.

obstetrics (noun)	medical specialty (noun)
the branch of medicine dealing with childbirth and care of the mother	the branches of medical science that deal with nonsurgical techniques