hCG can be extracted from placentas or the urine of newly pregnant women, but it's not made that way on a pharmaceutical scale anymore.
It's made via recombinant expression systems, though I'm not sure exactly which most Chinese producers would be using at present. It could be expressed in E.coli, recombinant insect cells, recombinant fungal cells, etc. Anything which could be cell-cultured on a large scale in a fermenter, and induced to produce the protein of interest in large amounts.
It's not economically viable to extract milligrams of hCG from the urine of thousands of newly pregnant women, or thousands of placentae... unless you were paying thousands of dollars per amp.
-M