Portuguese Citizenship - birth by Portuguese Mother

I was born in Zimbabwe to a Portuguese Citizen.
She gave me up for adoption in Zimbabwe.

I know children born to a Portuguese Parent are consider Portuguese at birth.
Does adoption make a difference?
Can i apply for Portuguese Citizenship?

I have all the paper work, ie, original birth certificate with her name.

Anyone else had this experience.

I know the UK, USA and some other EU countries allow it.  BUt cant find any information on Portugal allowing/not allowing it.

Do you have a legal birth certificate issued from Portugal ?
Would require further verifications if some paperwork exists in Portugal to recognize it.