In the book, Mae Coragem, released in Portugal Friday, Aveiro claims that she drank warm beer and ran "until she dropped" after the doctors had refused to terminate her pregnancy, reported the Independent.
"I wanted to abort but the doctor didn't support my decision," Spanish newspaper La Razon, which is serialising the book, quoted her as writing.
Aveiro said Ronaldo knew about the incident.
"He told me when he found out, 'Look mum, you wanted to abort and now I'm the one who's pulling the purse-strings in the house'."
Ronaldo, regarded widely as one of the best footballers in the world today, failed to inspire Portugal in the FIFA World Cup as they were ousted in the group stages.