With assistance, give birth (5)
I believe the answer is:
whelp
'give birth' is the definition.
(thesaurus)
'with assistance' is the wordplay.
'with' becomes 'w' (abbreviation).
'assistance' becomes 'help' ('help' can be a synonym of 'assistance').
'w'+'help'='WHELP'
(Other definitions for whelp that I've seen before include "Young wolf or dog" , "youngster" , "Produce issue" , "bear" , "Boy!" .)