Suzanne Doherty, 42, already had three girls when she went into hospital to have her cervix removed.
She was unaware she was 14 weeks pregnant until she came round from the anaesthetic to be told the unborn son she had always wanted had been terminated.
Suzanne was left suffering from depression after the operation, performed at the Royal Cornwall Hospital in Truro.
Suzanne was awarded £62,000 after the hospital admitted liability and a 'catalogue of errors' during the botched procedure in 2007.
The mum, from St Mabyn, Cornwall, said: "I was told the operation had been a success but unfortunately a foetus had been discovered and that the foetus had been terminated.
"I was told with just the curtains pulled, so there were other people in the bay that heard what had happened.
"It shouldn't happen in this day and age. There are so many checks. It shouldn't get to the point where a pregnancy was missed."
Suzanne said that following the operation she was physically well but had 'long bouts of quite bad depression'.
She said: "I would go back to work and then I wouldn't be able to handle it and I would be off again, which ended with me having to lose my job.
"Knowing the fact that we've got three girls and we could have had a son, that was absolutely devastating.
"It has taken me a long time to get to the point where I have accepted what has happened."
Suzanne's solicitor, Charlotte Skouby, said: "Following the removal of our client's cervix a 14-week-old foetus was discovered and the pregnancy diagnosed at which point, tragically, the pregnancy was no longer viable.
"The responsible NHS trust admitted the fact of the inadvertent termination and that the diagnosis of the pregnancy could and should have been made at the point when it was still viable, thus enabling our client to go on to term and deliver a much wanted baby boy."
Royal Cornwall Hospitals NHS Trust has apologised.
Lezli Boswell, the trust's chief executive, said: "I am deeply sorry to hear about any anxiety, pain or distress caused to our patients."