prematurely
adverb /ˌpreməˈtʃʊəli/
  /ˌpriːməˈtʃʊrli/,  /ˌpriːməˈtʊrli/
- before the normal or expected time- Her hair became prematurely white.
 
- before the normal length of pregnancy has been completed- The child was born prematurely.
 
- too soon- Tomatoes won't ripen if they're harvested prematurely.