Domestic birth upset quack (9)
I believe the answer is:
charlatan
'quack' is the definition.
(I've seen this before)
'domestic birth upset' is the wordplay.
'domestic' becomes 'char' (I've seen this before).
'birth' becomes 'natal' (I've seen this before).
'upset' says the letters should be written backwards.
'natal' written backwards gives 'latan'.
'char'+'latan'='CHARLATAN'
(Other definitions for charlatan that I've seen before include "Quack doctor" , "Quack, fraud, a flamboyant deceiver" , "Phoney" , "One who falsely claims to be an expert" , "Trickster" .)