Powder used in antenatal clinics (4)
I believe the answer is:
talc
'powder' is the definition.
(talcing is a kind of powdering)
'in antenatal clinics' is the wordplay.
'in' says the answer is hidden in the clue.
'TALC' is hidden within 'antenatal clinics'.
'used' acts as a link.
(Other definitions for talc that I've seen before include "Bathroom dusting powder" , "Toilet powder - mica" , "Perfumed drying powder" , "I may dust" , "Magnesium silicate powder" .)