we stil refer to almost having a miscarriage as a “threatened miscarriage”; however spontaneous abortion is used routinely to describe an actual miscarriage. Omitting the spontaneous aspect just seems lazy imo.
Actually, the whole thing is lazy, giving credence to the great statement of my college biology teacher: when you simplify, you lie.”
The two words are not synonymous - doctors have become illiterate. A spontaneous abortion occurs early on; often before the woman knows she is pregnant, and even after, she might not know what all the bleeding and cramping was about. A miscarriage occurs later, often involves labor. You lose an identifiable baby.