Not yet delivered (2,5)
I believe the answer is:
in utero
'not yet delivered' is the definition.
(in the womb, before being birthed or delivered)
This is all the clue.
(Other definitions for in utero that I've seen before include "Embryonic" , "Before birth - routine (anag)" , "Pre-natal position (Latin)" , "Within the womb - routine (anag)" , "Before birth (Latin)" .)