The preemie makes a fist and, summoning all his strength, punches through the glass case of his incubator.
"baby born prematurely," 1927, premy, American English shortening of premature + -y (2). Spelling with -ie attested from 1949.
preemie pree·mie or pre·mie (prē'mē)n. A prematurely born infant.
A premature baby: like a human preemie, it was placed in an Isolette (1927+)