Pregnant woman's doctor with the gown obtaining temperature (6-2-2)
I believe the answer is:
mother-to-be
'pregnant woman's' is the definition.
(woman expecting a baby)
'doctor with the gown obtaining temperature' is the wordplay.
'doctor with' becomes 'mo' (medical officer. I am not sure about the 'with' bit.).
'gown' becomes 'robe' (synonyms).
'obtaining' is an insertion indicator.
'temperature' becomes 't' (abbreviation).
'robe' placed around 't' is 'rtobe'.
'mo'+'the'+'rtobe'='MOTHER-TO-BE'
(Other definitions for mother-to-be that I've seen before include "Expecting woman?" , "One expecting a baby" , "She's expecting" .)