Comic routine 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)
'comic routine' is the wordplay.
'comic' indicates anagramming the letters.
'routine' with letters rearranged gives 'IN UTERO'.
(Other definitions for in utero that I've seen before include "being developed" , "Embryonic" , "Before birth - routine (anag)" , "Within the womb - routine (anag)" , "awaiting delivery" .)