Jennifer Burns, from Gauldry in Fife, took £950 from the bank account of 91-year-old Dr Alexina McWhinnie.
Dr McWhinnie was a renowned social researcher in assisted conception at Dundee University until her retirement.
At Dundee Sheriff Court, Burns admitted two charges of theft between 15 November and 14 December last year and will be sentenced next month.
Burns targeted Dr McWhinnie - who received an MBE from Prince Charles for her work - after she gave Burns her bank card and PIN number to withdraw cash on her behalf.
Dr McWhinnie told the court: "If you can't trust the people who look after you, then who can you trust?"
Fiscal depute John Adams told the court: "The complainer is a 91-year-old female whose family employs care services to assist her.
"On December 19 her son came to stay with her in the run up to Christmas and was checking her bank records when he realised something had gone awry. They reconciled this with information from the care firm and it was realised the accused had been the person there on the relevant dates."
Defence solicitor Scott Norrie said: "She (Burns) had accumulated a debt of £2,000 during a previous relationship that subsequently broke down.
"She had a reasonable relationship with the complainer and they got on well. She saw the opportunity to clear some of those debts and abused the trust of this lady.
"She lost her job as a result - but living with her parents continued to put up the pretence of having a job, leaving for work each morning and coming back at night. She is utterly ashamed of her actions."
Dr McWhinnie said she was "foolish" to give her bank card and PIN to Burns.
She said: "I foolishly asked her on one occasion if she would mind going to the cash machine for me as I struggle to get down there. I didn't realise straight away but somehow she must have been able to use my card over the next month."
Dr McWhinnie said she contacted police after she noticed a large sum of money was missing from her account.
She added: "She took advantage of my trust and it left me shattered. I felt as if I'd been cheated and it made me realise how vulnerable I am."
A carer has admitted stealing nearly £1,000 from a retired doctor she was supposed to be looking after.