obstetrics vs fetology

obstetrics and fetology both are nouns.

Word	Noun	Adjective	Verb	Adverb
obstetrics	Yes	No	No	No
fetology	Yes	No	No	No

As nouns, fetology is a hyponym of obstetrics; that is, fetology is a word with a more specific, narrower meaning than obstetrics:

obstetrics: the branch of medicine dealing with childbirth and care of the mother
fetology: the branch of medicine concerned with the fetus in the uterus

Other hyponyms of obstetrics include foetology, perinatology.

obstetrics (noun)	fetology (noun)
the branch of medicine dealing with childbirth and care of the mother	the branch of medicine concerned with the fetus in the uterus