IPA: /prɪˈmætʃərli/
KK: /priˈmeɪtʃərli/
In a way that happens too soon or before the right time.
The baby was born prematurely and needed special care.
Prematurely → It is formed from "pre-" (meaning before) and "maturus" (meaning ripe or mature) and the suffix "-ly" (meaning in a manner). The word "prematurely" means in a manner that occurs before the proper time or before maturity.
Think of something happening 'before' ('pre-') it is 'ripe' or 'mature' — that's why we say it happens prematurely.