1857 as a term in biology, "reproduce, grow by multiplication of elementary parts;" see proliferation. General sense, of things, etc., "increase greatly in numbers," by 1961. Related: Proliferated; proliferating.
word-forming element making adjectives from verbs, meaning "pertaining to, tending to; doing, serving to do," in some cases from Old French -if, but usually directly from Latin adjectival suffix -ivus (source also of Italian and Spanish -ivo). In some words borrowed from French at an early date it has been reduced to -y (as in hasty, tardy).
<a href="https://www.etymonline.com/word/proliferative">Etymology of proliferative by etymonline</a>
Harper, D. (n.d.). Etymology of proliferative. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/proliferative