non-viable (adj.)

applied to a fetus too young to maintain independent life, by 1821, from French non-viable (by 1813 in the Code Napoléon); see non- + viable.

It is an established fact, that under the fifth month no foetus can be born alive—from the fifth to the seventh it may come into the world alive, but cannot maintain existence. The French term these non viable. We may designate them non-rearable, or more properly immature—in distinction to those between the seventh and the ninth month, which may be reared, and are termed premature. [John Gordon Smith, M.D., "The Principles of Forensic Medicine," London, 1821]