Pregnancy hormone for good developing isn't blocked by drug (9)

'pregnancy hormone' is the definition.
'progestin' can be an answer for 'hormone' (progestin is a kind of hormone). I am not sure about the 'pregnancy' bit.

'for good developing isn't blocked by drug' is the wordplay.
'for' becomes 'pro' (as in being 'pro' or in favour of something).
'good' becomes 'g' (abbreviation).
'developing' indicates an anagram (letters developed into a new form).
'blocked by' means one lot of letters goes inside another (block can mean to plug a gap in something).
'drug' becomes 'e' (E is another name for ecstasy).
'isnt' with letters rearranged gives 'stin'.
'stin' going around 'e' is 'estin'.
'pro'+'g'+'estin'='PROGESTIN'

Can you help me to learn more?