The guilty plea of a woman serving a six-year prison sentence in connection with a child's drowning death in Youngstown has been withdrawn.

According to court records, Judge Maureen Sweeney granted a motion to withdraw the guilty plea of Adrienne Hudson, who was sentenced to six years in prison for the drowning death of one-year-old Londyn Cayson.

Court documents state that when Hudson entered a plea deal in August, she was promised a minimum sentence of five years in prison in exchange for her guilty plea. However, on her sentencing date in October, Hudson was sentenced to six years.

"As a consequence, [Hudson's] plea was not knowing, intelligent and voluntary and the court must permit her to withdraw her plea and/or vacate said plea," the document reads.

"There is a provision in the criminal procedure that allow for a defendant to withdraw a guilty plea but it is very unusual for a judge to allow a defendant to withdraw a guilty plea," said Jonothan Entin, law professor at Case Western Reserve University.

Legal experts say it's uncommon to see a guilty plea withdrawn before sentencing, and that it's even more rare for removal of the plea to be granted after the fact.

"Based on the ruling of Judge Sweeney, she agreed that in fact that this wasn't a knowing, intelligent plea because this defendant was expecting one thing, in five years, and something different, six years," said Matt Mangino, former defense attorney.

Mangino says it could go a number of different ways from this point moving forward.

"Do you negotiate a new plea agreement? Do you negotiate a plea agreement that makes it clear that the court can go above or below what is being recommended by the prosecutor," added Mangino.

Court records show a new pre-trial hearing for Hudson has been set for December 11.