37-year-old Kelly Harrop had been on her victim's care rota for some two years when she committed the offence on May 21 this year, Sheffield Crown Court heard.
David Wain, prosecuting, described how the 90-year-old woman suffered from both dementia and advanced Alzheimer's, and received regular visits from carers employed through Direct Health.
The court heard how it was normal practice for carers let themselves into the woman's property with a key stored in asafe outside the entrance to her home, and for her son-in-law to leave cash he had withdrawn for her in the property.
At the time of the offence, Harrop, of Dunscroft, was off work due to sickness; but a neighbour observed her arriving at the complainant's property dressed in her uniform shortly after the scheduled carers' visit to her home was due to have finished.
"It's the Crown's case that she had no lawful excuse to be there, and was wearing the uniform as a disguise," said Mr Wain.
After her neighbour noticed a second carer, who was running 40 minutes late on her rounds, arrive at the property a short time later, he raised the alarm.
Mr Wain added: "The key safe code was changed, and after a check was carried out they realised Â£70 of the money cashed from her pension was missing."
Harrop, who has no previous convictions, pleaded guilty to a single charge of theft at an earlier hearing.
Cheryl Dudley said in mitigation that Harrop was currently in the 'midst of a very difficult domestic situation,' for which she was receiving advice from a women's centre.
She asked the presiding judge, Recorder Duncan Smith, to take this, as well as her good character and early guilty plea into consideration when passing sentence.
Recorder Smith sentenced Harrop to nine months in prison, suspended for two years, and ordered her to repay the Â£70 she stole.
"You, of course, being a mature lady, and a mother, know just what a shameful thing it was that you allowed yourself to do," said Recorder Smith.
He added: "But for the reasons I have been discussing with your advocate, and the matters raised in the pre-sentence report...I am of the view they allow me to take an unusual course and suspend your prison sentence."