A mother-of-three dishonestly claimed £2,900 in benefits after the father of one of her children moved in with her.
Erika Hughes was sentenced to a curfew of 28 days at Teesside Magistrates' Court.
The bench chairman told her the offending amounted to 'theft from honest claimants'.
Prosecutor Joanne Hesse said Hughes began claimng benefits in 2014.
"She did so as a single mother with no other income," added Ms Hesse.
"In January of 2017 her partner moved in, but she failed to tell the authorities.
"The claim was dishonest for a period of six months, and the total overpayment was £3,973."
Hughes, 29, of Golden Meadows, Hartlepool, admitted two offences of dishonestly failing to notify a change of circumstances between January and July, 2017.
She was of previous good character.
Daniel Burke, defending, said: "This claim was not fraudulent from the outset, it was honest from the outset and remained so for a long time.
"I suppose it comes down to when someone moves in.
"It was a gradual process, Ms Hughes' partner went from staying occasionally to staying for longer, to moving in.
"Ms Hughes became unexpectedly pregnant, and she put this matter on the back burner.
"She did eventually contact the authorities to tell them her partner had moved in, but was told they already knew and were making inquiries."
The court heard Hughes is repaying the £2,900 via a £74 monthly deduction from benefits.
"She is repaying money she would have been entitled to," said Mr Burke.
"Had she informed the authorities in January, it seems certain the benefit would have been allowed to continue because her partner had no income.
"This offending continued for six months, which sounds a long time but it is a relatively short period of time for this type of offending.
"Ms Hughes is a mother of three children.
"She is ashamed and embarrassed by her conduct and wishes to apologise to the court."
Hughes was sentenced to a curfew of 28 days and ordered to pay £170 costs at £5 a week.