Panorama - The Great Abortion Divide, will explore whether doctors in England are signing off terminations on questionable mental health grounds.
Professor Gerada said it should not be a GP's role to question whether a patient was presenting with genuine mental health issues or not.
She said: ‘There isn’t a blood test that can predict if someone’s going to get mental health problems.
‘As a GP I’m there to help a woman through one on the most difficult times of her life, to help her understand her options, it is not for me to call her a liar.’
Professor Gerada will appear on Panorama – The Great Abortion Divide on BBC1 at 8:30pm tonight.